Heathrow Airport's Terminal Two was closed for an hour and a half on Friday after a "suspect package" - later declared safe - was found.

Two people arrested in Hounslow, near Heathrow, on Thursday have been released without charge.

Anti-terrorist police have handed four others over to the immigration authorities, after separate arrests on Thursday in Langley, Berkshire, near Heathrow.

Meanwhile a 37-year-old Venezuelan man is still being questioned by police, after being caught trying to smuggle a live grenade through customs at Gatwick.

Have your travel plans been affected by the increased police and army presence? If you live in the surrounding areas, have there been many changes to your daily routine? Are these measures an effective means of preventing any possible terror attacks?

Thank you for your comments; this debate is now closed. A selection of your e-mails is published below.

I have just flown back from Florida, where the tension is just as palpable. There are constant warnings that thre may be an attack before the weekend. I found the security measures at Orlando airport quite reassuring.
Jackie, England

People have to realise that our security forces know what they're doing! Mike, Scotland

Why are people so blinkered? The government aren't telling us because by doing so there would be a security risk. Face it, given the choice we wouldn't tell the government about our jobs, pay, back handers etc if we could get away with it. For goodness sake, this is serious, it's our nations security at risk, people have to realise that our security forces know what they're doing!!
Mike, Scotland

The tank is there as a show of force - of course it has no practical use, it is merely a deterrent. I am glad our politicians are not as stupid as some of the people leaving comments on this site!!!
Jon, UK

It's a very confusing and worrying time for us all! Cheryl, UK

I am due to take my husband on a suprise 40th birthday treat to NY at the beginning of March - a trip that has been planned for months. I am confused by the information (or lack of it) from the government and annoyed by the speculation by the media. Should I cancel the trip now and risk losing all my money or do we carry on regardless? It's a very confusing and worrying time for us all!
Cheryl, UK

As Eileen said "Public safety is too serious an issue to be used in that way" so heads should role and the person responsible for this pathetic American-style scare mongering should spend a few days in jail.
Shane, Switzerland

Who are we at war with Lauren? A terroist attack in NY; they still don't know who did it. Many thousands more dead in Afghanistan (that's why some think the US are terrorists). The "fear" is nurtured in the public by the government to do what they want. How many vague threats and warnings without actual attacks in the last years. Heathrow is the latest publicity stunt.
Jonka, Switzerland

The troops at the airport are the visible sign of reassurance Roger Pope, UK

I for one feel a lot safer with the military presence around. The troops at the airport are the visible sign of reassurance. There is plenty going on that the general public don't see. As for a publicity stunt well, I think that is rubbish. And as for the comments re being at war from some of our American friends, yes we know, we've lived and people have died with that for the last 30 years in this country from the IRA.
Roger Pope, UK

I agree we must not live in fear. Instead we must address the problems facing the world at the moment. It is one of the reasons why we face terrorism now. It certainly sounds like paranoia from 10 Downing Street, over this terrorist threat. Instead of finding positive solutions to the world's problems, it's dragging us further into more danger from these terrorists. Please Mr Blair resign now. Let somebody more capable run the country, you certainly can't.
Gary Turner, France

The timing of these threats seems too coincidental with the threat of war looming. The US government has a long history of using propaganda to control public opinion and I fear those methods being employed in this country more than any terrorist threat. And with all due respect to the Americans and London citizens voicing their fears on here - having lived in London all my life I've lived under the threat of IRA and other terrorist atrocities; something clearly these people have no experience of.
Peter Fuller, England

We're at war people, this is what happens when we're at war. Get used to it.
Lauren, USA

Lauren, USA - With that attitude, Osama has not just killed thousands on 9/11 but destroyed all our lives. Naive maybe, but today, I'd like to live without war and won't stoop to his level. He went for maximum effect and maximum hate and I won't let him ruin my life!
Angie, UK

The politicians seem to be more interested in protecting those who live in the south eastern corner of Britain Malcolm Scott, Scotland

If there really is a threat to the security of passengers on board flights from Heathrow in the form of anti-aircraft missiles, of what possible benefit is a tank, parked outside the front of the airport, to the 'increased' safety of those who are flying? This is, sadly, just another show for the cameras that the government would have us believe is necessary for national security. I would be interested to know just how many people outside of the capital are as concerned about security, as the politicians seem to be more interested in protecting those who live in the south eastern corner of Britain.
Malcolm Scott, Scotland

I don't believe that Tony Blair would have any reason to deploy so many troops and extra police officers if he didn't feel that there was a truly serious threat to the public. The public seem to be so cynical when really we all need to realise that this country isn't particularly any more popular with terrorists than the USA.
Jodie, England, UK

I'm amazed at the anti-Blair comments here. This is not a party political issue. I'm sure that the Tories and the LibDems would respond to a threat in a similar way. It's inconvenient I know, but we'll live with it. Hopefully the terrorists will be scared off. This is part of an ongoing campaign against them, there have been arrests all over Europe after all. Live your life, otherwise they've won!
Rob, UK

The police presence seemed no higher than usual either Stephen Smith, England

I'm a flight attendant and got back from Washington on Wednesday morning at around 7am. I didn't know what to expect when I got back to England as there had been a lot of media coverage in the US about the increased security at British airports, especially Heathrow. On my return I was surprised to find no troops outside terminals two or three or the 'Concorde' roundabout as I had clearly seen on TV the day before. The police presence seemed no higher than usual either. Apart from a bored looking pair of soldiers on foot in a car park off the perimeter road I saw no signs of increased security. I simply do not know what to make of this - is this just a publicity stunt because if it isn't then I'm worried - the extra protection just wasn't there.
Stephen Smith, England

Today I received an e-mail from a friend asking if it was safe to visit London on Saturday. I also know people who cancelled a trip to support England in last night's football. Fear is real.
Simon, London, UK

Having worked at Heathrow for nearly 17 years and been through several terrorist attacks here, I can say that the troops are a welcome deterrent but with great respect, it won't matter. A determined terrorist would have planned and practiced an attack for some time if they were going to do it. If it's going to happen it's going to happen, whether it's bin Laden or some other unknown group or faction. Carry on normally, live your lives.
Martin Craggs, UK

Unfortunately for Blair I never felt unsafe. Blair has spun so much spin and told so many lies to try and make us follow him into war, he now believes it and has frightened himself to death. The only way of overcoming the fear of his own imagination is to deploy troops and try and frighten the public into believing his lies.
Paul, UK

We are living in very scary times Karen Kinsella, London, UK

I think we are living in very scary times. I don't travel by tube anymore for fear that if there was a suicide bomber or a gas attack, we quite simply wouldn't stand a chance. It's awful that in these times, we need to constantly be looking over our shoulder. We have enough on our plates with general crime in this country without the added threat of terrorism. It makes one look to consider getting out of your country and moving abroad to feel safe!
Karen Kinsella, London, UK

I am concerned and angry over these people who accuse the government of hype in respect of the extra security put into place at Heathrow, saying that the government is only doing this to make us more agreeable to a war. These people are a danger to the security of our country and should be questioned by the police to ascertain that they are not enemies of the UK.
Peter B, UK

We will not travel as the risk is too great Sue, Portsmouth, UK

I am due to fly out of Heathrow on Friday on a British carrier for a 'once in a lifetime' trip to New York with my husband. I find the lack of information disconcerting as I wish to make an informed rather than emotional decision. I feel that at the end of the day we will not travel as I have three young children at home. The risk is too great.
Sue, Portsmouth, UK

It's all scaremongering by Blair. He wants us to believe there is a threat, to justify his stupid war with Iraq. Surely, if something was going to happen it would have happened by now. Where did all this come from, it just came out all of the blue. I am sick and tired of Blair trying to justify this war, at our expense. It's time that he and his government, stopped playing the poodle to Bush and get on with tackling the real threats to this country - crime, unemployment etc.
Steve Price, UK

I am more worried about my train coming off the rails than a terrorist attack M Khan, UK

This country is literally spending billions on security, it should be given some credit at least. I mean we have a system in place, a system which hopefully works, we have emergency terror evacuation measures in place, so why be scared to death. I am more worried about my train coming off the rails than a terrorist attack - honestly.
M Khan, UK

I am prepared to accept that al-Qaeda might perpetrate an atrocity to "celebrate" Eid. The IRA planned Christmas bombing campaigns and there are well-documented examples from around the world of different religious extremists using their own holy days to score points. I also believe that there is a real threat to the UK from al-Qaeda and that they are attempting to whip up sectarian hate in sections of the Muslim community.
Sy, UK

It's all very well ploughing money into high tech prevention, but there seems to be little thought into the nature of previous attacks. How can increased security realistically guard against a suicide bomber? They do not have to use complicated devices to create a disaster
Trudy, London, UK

It is time the British public woke up and accepted that the terrorist threat to our communities has never before been greater. Anyone foolish enough to point the finger at Blair and to accuse the British Government of using scare tactics in order to drum up enthusiasm for an offensive on Iraq would do well to cast their minds back to the atrocities of 9/11.
Simon R, UK

It strikes me that the same people who say that this is just a publicity stunt, are the very same people who would complain loudest if there was an incident and not enough preparations had been taken, or not enough warning had been given.
Bjorn Lynne, UK

Real threat or scaremongering stunt, we'll not know unless something does happen. If the government hadn't previously cried wolf we might have more faith in them. I for one have none, at the moment.
Andrew, England

Further paranoia can only be avoided if we have real information Peter Logan, UK

My wife and child are due to fly from Heathrow to Washington on Thursday and I am now very concerned that we are not being given enough information about the threat to enable normal people to make an informed decision about whether or not they should fly. In the absence of any real information, I would like to ask Tony Blair - "Would you send your wife and child on a British carrier flying from Heathrow to Washington this Thursday? Further paranoia can only be avoided if we have real information and clear guidance from the government.
Peter Logan, UK

In NY City we all wish the US had been on high terror alert prior to 9-11. You should be thankful if nothing happens, not complaining about this being a game. Three thousand dead is no game and the fundamentalist terrorists hate you as much as they hate us.
Craig, New York, NY, USA

I hate to tell you people who think this is a stunt...it isn't. As an ex-solider I know that the army would only deploy like this if there was a definite threat. So please don't be so naive as to think that the government is just doing this to get support.
Wayne, Sunderland UK

Every day I tell my wife and children how much I love them Bob, England

I commute right through London every day. I accept that I could be caught up in a terrorist attack during that journey in the next few days. I make absolutely sure that every day I tell my wife and children how much I love them, just in case. Other than that, life goes on as normal. I also accept the possibility that this is a false alarm, or worse part of a propaganda exercise. Only time will tell.
Bob, England

I am worried that the threat seems to be worsening. My husband flies into Heathrow tonight from Frankfurt. His flight number is BA 911 - I hope that the intelligence services have picked this up
Barbara Collins, England

I think it is good to see the extra security. But why is Tony sending 30,000 troops to the Gulf when they should be kept here and deployed to defend the UK from terrorist attack?
Brad, UK

There were no security checks being made Dave Tinham, England

I work at Terminal 5 and my journey to work today took an hour instead of 15 minutes because 2 police cars were parked in the road at the busy Clockhouse Lane roundabout. There were no security checks being made, in fact the car's occupant appeared to be asleep. The disruption caused seems to me to be doing the terrorists' job for them with very little to be gained for any of us
Dave Tinham, England

I fly in and out of LHR on a regular basis, mainly to New York. If the threat is really a SAM attack then what use is a tank? Do they intend to fire back? The reality is that such an attack is only preventable using counter intelligence so the whole exercise is show. The threat is real enough, this reaction cannot prevent it.
Terry Boyland, England

Having lived in Hounslow for many years it has disturbed me to think of the awful consequences of an aeroplane being brought down in that area. Why is it only Heathrow and Manchester Airports that are at risk, surely there should be heightened security at all the major airports in the UK.
Alan Taylor, UK

Blair is trying desperately to justify his war with Iraq Vish, UK

Blind paranoia and nothing else. Blair is trying desperately to justify his war with Iraq and this is an excellent way to do it. Scare the hell out of the populace.
Vish, UK

This is scaremongering in the extreme, a life lived in fear is a life half lived. There have always and will always be disgruntled extremists. I for one will not support this war, I intend to march on Saturday to voice my dissent and all this propaganda will not discourage me one little bit. Vive peace
Claire, UK

As a user of the London Underground I am concerned to see the low level of security on a network that is so vital to the business sector of London. With the latest threat on Heathrow the tube system could be seen as an easy target for terrorists. The network runs directly into and under all the main terminals, with easy access and escape routes at Hatton Cross and Hounslow West. Have all the risks been truly accessed?
Mark Croucher, UK

I live and work in Central London and am finding myself on edge waiting to hear an explosion of some kind. I have not been this nervous about an attack since the days immediately after 9/11.
Noel, London, UK

Is anyone else wondering just how wise it would be to fire off a few rounds from a TANK inside an AIRPORT?
Andy Jowett, UK

These terror alerts are very conveniently timed when public opinion really needs to be manipulated!
YK, UK

I am appalled that so many people think that this is nothing more than a publicity stunt Mandy, UK

I am appalled that so many people think that this is nothing more than a publicity stunt or an attempt to overshadow the peace protests on Saturday. There has been very real intelligence about attacks on the US and its allies at the end of Eid. I would much rather see heightened security than see an attack on the scale of Sept. 11 and I don't believe even our government would stoop so low as to pull such a cheap stunt.
Mandy, UK

A lot of people are complaining about this increase in alertness. Well if something did happen and there were nobody there to deal with it what would happen then? They would complain about it?
James Cardwell, Manchester, England

Fear is power. This is a poor attempt to make people paranoid and afraid, and thus easier to control and manipulate. The US Governments have traditionally been doing this for years (see Cold War tactics for reference) and now it's being used on us in the UK too. Nice timing I must say, considering the US is looking to start the war towards the end of this month or very soon after.
Anon

It is correct to take all the measures against possible terrorist threats. Terrorists must be stopped.
Walace Rodrigues, Amsterdam, the Netherlands

Re Michael Thomas comment. I also live in a village on the Heathrow boundary and while I can understand the police presence I wonder just how a tank is going to chase after someone that has fired from the boundary into the airport. Any terrorist would be long gone before a tank managed to get to the perimeter road
Elizabeth Lloyd, England

There is obviously a very clear threat to airports in this country Michael Thomas, UK

I live in one of the villages close to the airport and this morning was something I've not seen before, the numbers of police are very visible and stopping cars. On the way to work, I have never seen the large numbers of police checkpoints on slip roads on and off the M4 towards Windsor. If anyone is stupid to think this is a publicity stunt, think again. There is obviously a very clear threat to airports in this country. 1,000 police officers are involved and 700 soldiers at Heathrow alone. God forbid if they down an airliner over a large town. It will be our own version of 9/11.
Michael Thomas, UK

I'm travelling on Friday and am dreading anything happening to delay my trip - yes, selfish I know. But I do feel more secure with the troops about than without - it makes me feel that an attack is less likely. There is an ever present threat of terror these days and people will have to get used to sights like this, but at the end of the day, that is what the army is for - to protect the country and its citizens.
George, UK

Having just flown out of Heathrow to Manchester I see no reason why not to boost security. Whilst I'm not sure the threat has indeed increased I'm not seeing the information that would be available to the government. At the end of the day though, it will boost the visibility of our Armed Forces in the eyes of the public and provide training/ experience for similar operations in the future if deemed necessary.
Nigel Brodt-Savage, UK

Tony Blair knows what must be done Andy, UK

The threat is indeed real. The people behind it care neither for the 'peace movement' the 'peace march' the FA Cup Final, the price of fish and chips or any other facet of our way of life - they want us gone. On this issue of global terrorism Tony Blair knows what must be done and he gets my credit and support for having the guts to take the right as opposed to the supposedly popular course of action. (and no I did not vote for him).
Andy, UK

I'm flying out and into Heathrow tomorrow but thankfully not on a UK or US carrier. I believe this security alert is fabricated but not unfounded as should the West ever attack another Muslim country all facilities will need extra security for ever.
Derek Davey, UK

Firstly, as a Muslim I feel insulted that the government should say that there is a terrorist threat surrounding the celebration of Eid. In order to garner public support for a war against Iraq, the government is trying to instil fear into the populace. What amazing timing to correspond with the peace rally on Saturday and the tape of Osama bin Laden revealed yesterday.
H. Schmitt, UK

I have yet to speak to a single person who is not reassured by this act Simon, England

I am very comfortable with the use of troops at Heathrow and now Manchester. Indeed, in these times of uncertainty, why not place them at every airport? I have yet to speak to a single person who is not reassured by this act.
Simon, England

I'm currently working in Belgium and will fly back to Heathrow on Friday. The thought of a possible terror attack is worrying but I am reassured that the extra police and military are being deployed. I don't believe it is a stunt to make the UK population support a war with Iraq. Public safety is too serious an issue to be used in that way
Eileen, UK

I am flying out on Thursday 13th to Los Angeles from Heathrow and am very apprehensive about it. I for one am happy that the government is 'paranoid' enough to take steps to try and protect its citizens.
Gus Swan, UK

I think it's propaganda. Lack of mass support for this war is worrying the UK and US governments. I have no idea how much of a threat Saddam Hussein is to us in the West but I do know that to wage war with Iraq will be to continue the very course of action that has given rise to so much anger in the Middle East. Attacking Iraq will do nothing to counter terrorism against the West.
Kulu, UK

The lack of information is more than alarming Tim Swain, Wales

My son is due to take a flight to Australia this evening from Heathrow. I have been absolutely terrified by this news. The lack of information is more than alarming and the absence of direct simple advice from the authorities as to whether it is safe to travel from the airport or not is very telling. If the danger is so great, shouldn't they close the airport?
Tim Swain, Wales

Rather a coincidence that this is occurring just at the point that a large peace demonstration is planned in London on Saturday....!
Jayne, UK

I agree with Steven from Leicester that the government would not be taking this action if there wasn't a real threat. However, I don't like the fact that this threat has been made so public. Of course people have a right to know if they're at risk in any way, and of course you can't conceal the huge increase in force at the airports, but in making so much of this public we are also sending a clear message to those who would do us harm, i.e., whilst we're focussing on the airports they're pretty much free to go ahead and do something terrible somewhere else.
Sara Dawson, UK

I personally feel that the government would not increase security to this level as a mere publicity stunt, and that there must be a specific identified threat.
Steven Leicester, UK

It's paranoia being used to control the masses. I recently visited the US on a business trip and was stunned at the level of paranoia and nervousness there, and the media in their country is the chief culprit in stirring up this level of hysteria.
Dave, Dublin, Ireland