He has been in the front line of Scottish politics for 15 years and an activist for all of his adult life.

The 40-year-old was elected MSP in the country's new devolved parliament in 1999. He was joined four years later by five other SSP MSPs.

It emerged last month that the party was expected to go �200,000 into the red by the end of the current financial year.

Mr Sheridan conceded then that the SSP faced "a potential deficit" but said it was determined to "come through this even stronger".

These emails are a selection of the comments you sent us.

Much as I didn't agree with his beliefs Tommy Sheridan clearly cared and believed in what he was doing, unlike the majority of politicians. If nothing else you could always feel confident that he was being honest.
Fiona, Dumbarton

This may be a setback for the SSP but we will come out stronger than ever. illegal wars, poverty and injustice were issues yesterday, and they will still be issues tomorrow. What we fight for has not changed.
Donnie Nicolson, Glasgow

Is he leaving to spend more time with his sunbed?
Oscar Apfel, Dumfries

Tommy Sheridan isn't about politics, he is about being in the spotlight loved faultlessly and not having to earn his position of power. He is no different to Arthur Scargill or Walter Mitty. I am amazed and concerned that Scottish people in particular are susceptible to these daydreamers.
Robert, Glasgow

Rosie for leader! The SSP needs a strong woman who stands up for her principles.
Andrea, Stonehaven

A political behemoth who towered head and shoulders over all the others in the Parliament, whose progressive, forward-thinking politics stood in stark contrast with those of the "charisma vacuum" that is the current First Minister McConnell. Tommy - you will be sorely missed, and I wish you every success in the future. Keep the red flag flying high.
James, Edinburgh, Scotland

Now we only have George Galloway to be ashamed of in Scottish politics! Good news.
Ewan Bowers, Dundee

I didn't agree with all of his opinions, but I would fight to the death to let him have the right to air them!
Gordon Goldie, London & Renfrew

Whilst I don't agree with his politics, people like him are good to have in the Scottish Parliament, at least he makes a change from the usual lot of sheep following the party line.
Ian, Aberdeen

Good luck to Tommy and I hope he enjoys bringing up his new baby. And his new labour political opponents shouldn't relax. He'll still be around as an MSP to stand up to their tricks.
Alister, Edinburgh, Scotland

Okay, so an SSP government wouldn't be realistic on the long term, but these politicians do play a role in demanding the executive are accountable to their actions, highlighting discrepancies in policy and generally preventing the executive from forgetting who they were elected by and who they are accountable to. Plus, they always add a bit of fun to proceeding and liven up the dull world of politics!
Camille Malinverno, Dundee, Scotland

You might not have wanted him running the country, but Tommy Sheridan is unquestionably a man of honesty, integrity, and he speaks for a group often ignored by the mainstream, even when it's not 'popular'. I'd have thought those were qualities we'd want in our politicians.
Matthew Egan, Edinburgh, Scotland

I live in hope that the people can educate their minds a little better and see that socialism is truly the best option for any country and is not the impossible dream made out by other more ignorant individuals. After all how can you argue against equality
Carla, Clydebank

Shame to see one of the few straight talkers left in Scottish politics resigning.
John Flynn, Alloa

Although not fully agreeing with the manifesto of the SSP, Sheridan was always a delight to watch in Parliament and spoke with passion which is a rare occurrence in politicians these days. Surely signals the end of the SSP however.
Craig, East Kilbride

When you vote for a system that has proportional representation you have to accept that you will get "characters" like TS. I for one will not miss him. Given that he will now have more time on his hands I can only assume that the SSPs loss is the tanning studios' gain.
Stuart Hay, Dunbar

At a time when Labour have gone so far to the right the SSP would surely have gained more support at the next election. Is there anybody out there who can take over and seize this opportunity?
John, Glasgow

One less ego to worry about in the Scottish Parliament. Good news
Lee, Edinburgh

Without Tommy the SSP will take a good spanking at the polls.
P Gordon, Scotland

Tommy was a rarity in politics, in that he was a man of principal, willing to stand up for what he believed, whatever the consequence. It is just a pity there are not more politicians like him. His forthright views will be sorely missed and it is sad to see one of the few champions of the working classes taking a step back.
Liam, Glasgow

I only hope that whoever replaces him as leader will have the same integrity and courage that Mr Sheridan has shown.
Peter, Perth, Australia

Tommy was an able leader ultimately fighting for an ideology that now all but defunct - without him at the helm his party will probably fall further into debt and remain on the fringes of real politics, an anachronism in today's political reality.
Iain Mc Mullan, Singapore

A politician that knows when to call it a day - respect to that man! He's been a true inspiration to the people of Scotland, a man of principal who fought for issues that really matter. All the best Tommy!
Gogs, Aberdeen

Tommy will be sorely missed. I vote SSP, but have always been concerned with some of its internal groupings and do feel that they will struggle without Tommy.
Kevin, Paisley

A sad day for Scottish politics. TS brought back the socialism that Blair and his cronies sold out for power and a red rose. The party will go under without him.
Bobby Killoran, Langbank, Scotland

It is unfortunate that Tommy Sheridan has resigned (regardless of what the reason may be). I believe his party will be the "poorer" for his less public input ... nevertheless, I'm sure he will still be battling behind the scenes. All the best.
Elizabeth, Glasgow

All this shows is that Tommy couldn't cut it as a leader. Just like Alex Salmond before him, as soon as they had to lead a team they couldn't cope. Both are only interested in furthering their own ambitions. Faced with the challenges of team leadership Alex Salmond and Tommy Sheridan ran away. As David Brent would say, there's no I in team but somewhere in there you will find me!!
John, Livingston

Although I disagree with much of the SSP's policies he was one of the few MSPs that I would take the time to listen to and I felt that Tommy believed in his ideals no matter how far fetched they sometimes appeared. The vast majority of MSPs are a complete waste of time as is the whole concept of a Scottish Parliament. It appears to me that it simply serves as a vehicle to cronyism rather than the Scottish people.
Adrian, Glasgow

Sheridan was the party. They will be lost without him. It looks like it will have to change its registered, official name from "Scottish Socialist Party Tommy Sheridan Convener".
Martin , Aberdeen

Scottish politics are grey, dull and a waste of everybody's money. Good on Tommy for doing the right thing, and may the rest of Holyrood follow suit.
Aloysius Munn, Edinburgh

I liked Tommy Sheridan but never saw him as a leader. I also like Alex Salmond but don't see him as leader either. That's the problem with politicians of their ilk. They can perform well on there own but when it comes to leading a large group of MPs or MSPs they get out. Its a shame he couldn't cut it.
Jannette, Bathgate

This will be a real test for the SSP as Tommy was the only coherent member they had in the public domain.
N MacLeod, Carnoustie, Scotland

I see the despicable end of Scottish politics here have jumped on Tommy's grave while the soil is still fresh. With New Labour engaged in the massive destruction in Iraq, supported in this war by the Tories and in power by the Liberals, the SSP has been the sensible, Scottish voice of opposition to this war, along with other Establishment injustices. Tommy might have changed his job, but I doubt he'll be going away quietly. I am a member of the Edinburgh South branch of the SSP, a branch full of intelligent, compassionate, uniquely humane individuals.
Martin J.G., Edinburgh

I may not have agreed with all of the SSP policies, but I respect Tommy Sheridan. He may not be from the same political mould as the uptight Tories or the pandering Labour MSPs, but that is what is so refreshing about him, and the rest of the Socialist MSPs. He related to people that may have been disaffected or excluded from politics and the front bench needs people like that. The Scottish Parliament, if it is to be truly representative of the population, needs loud-mouths, needs activists and needs "personalities" if only to find ways of forcing issues that must be discussed and bringing a human face to what is otherwise yet another group of grey suited civil servants. The SSP should not see this as a time to disappear, but more a time to focus on the future.
Alison, Edinburgh

Excellent news! The latest (and hopefully the last) in a long line of militants, whose adolescent policies and outbursts this country will not miss.
Mark MacClennan, UK

Socialism has failed in every country of the world that it has been tried in. Tommy Sheridan and his band of "Brothers and Sisters" have no idea of the impact their policies would have on our country. Politics is better of without him.
Robert Campbell, Alexandria, Scotland

About time! The guy was a loud mouth and his politics are unrealistic. Maybe the next leader might start thinking about what is best for Scotland. On the other hand though, it is pretty fair to say that Sheridan was the face of the party and it's unlikely now if the party will be able to keep gaining representation without him at the forefront of the party.
Greg, Glasgow

Perhaps TS could join (salary free of course) the police force or prison service if only to appreciate the time, effort and expense wasted in having to control the practices of "politicians" of his kind.
RD, Scotland

Very surprised by this news. The SSP has been built up around the "cult of the personality" of Sheridan, so I imagine its support will now dwindle away to nothing. They jump on every "popular" bandwagon which they think will get them votes, but I think without Sheridan people will see through them.
Karen, Glasgow

This is the end for the SSP. There is nobody there with the charisma of Sheridan, nor with his eye for political opportunism. The party is in debt and now without a leader, their bubble has well and truly burst.
Mark McDonald, Aberdeen, Scotland

More than anyone else in the Scottish Parliament, Mr Sheridan indulges in cheap political stunts which belong in student unions 20 years ago. At least now we'll be hearing less of him in the parliament - most of his ranting speeches consist of conjecture disguised as fact.
Simon, Edinburgh, UK

Anyone who thinks this is a disaster or the beginning of the end of the SSP, does not know this party. They will keep fighting for socialism and supporting the struggles of the working class. Thanks to Tommy, he will be missed by those faces persecution and poverty.
Bill Leary, Glasgow