What a British consul can do includes:

Visit prisoners as soon as possible Give details of English-speaking lawyers and the legal system Pass a message to prisoners' families Ensure medical problems are raised with a doctor Help find an interpreter

If a UK national has broken the law abroad, they should expect the full consequences of that country's legal system - however primitive or harsh.

Of course, the FCO has obligations to ensure fair treatment and conditions and often goes much further than the laid-down requirements, but it cannot secure better treatment than is given to locals.

The British consul will contact a prisoner after being notified of their arrest and will visit as soon as possible.

Medical problems

He or she will also give information on suitably qualified English-speaking local lawyers and the legal system, including details of legal aid (if available) and prosecution, remand, bail and appeal procedures.

Messages can be passed to the prisoner's family, and money can be sent via the consul to the prisoner.

What a British consult cannot do:

Secure better treatment than is given to locals Give or pay for legal advice or start court proceedings Investigate a crime Pay for prison comforts Forward parcels on behalf of family or friends

Any medical problems or complaints about treatment can be investigated.

But the consulate will not give or pay for legal advice - something which is often wrongly assumed.

Neither will it investigate a crime, pay for prison comforts or forward parcels.

This is where organisations like Prisoners Abroad and Fair Trials Abroad (FTA) might come in.

FTA is a charity established in 1990 by British lawyer Stephen Jakobi following widespread public outrage and concern generated by the case of Karen Smith, a British citizen arrested in Thailand and tried without proper legal representation or redress.

'Rage'

As well as campaigning for global fairness in law, it gives legal advice directly to prisoners held overseas. It can also give grants to help pay for lawyers, although these depend purely on public donations.

Mr Jakobi agreed there was "a misconception" about how much the FCO could do, and explained his organisation tried to work closely with consuls to plug any gaps.

The guilty should expect to be punished

"The FCO cannot give legal advice - we can," he said.

"We are lawyers. Yes we have to work through local lawyers - there is no way we could stand up in hundreds of different countries and states and know the individual law of each - but we can supply the international law component that may be missing."

Unlike the FCO, Fair Trials Abroad may also be called on to help with the actual investigation of a crime, in some cases even gathering evidence and statements.

"When you suffer a miscarriage of justice and you have been arrested for something you did not do, you will have a sense of rage, as will your relatives, and that may transcend you being reasonable," Mr Jakobi said.

"Quite obviously your first reaction will be to wonder where the Foreign Office is and ask why they are not securing your release. That is when we have to work together."

This though, only applies to those who are innocent - the guilty should expect a penalty.