Tony Blair made a grovelling apology to Colonel Gaddafi for failing to send the tyrant’s enemies back to Libya to face torture, the Mail can reveal.

The then Prime Minister told the dictator he was ‘very disappointed’ Britain’s courts had blocked the deportation of five Libyan dissidents amid fears they would be mistreated.

In a fawning letter on official Downing Street-headed paper, he thanked the despot personally for Libya’s ‘excellent co-operation’ in the controversial attempt to return the political exiles into the ruthless regime’s clutches.

Tony Blair pictured with Colonel Gaddafi in 2007. A letter seen by the Mail shows the then Prime Minister told the dictator he was 'very disappointed' Britain's courts had blocked the deportation of five Libyan dissidents

It was sent following a period in which Britain colluded with Libya to hand over terror suspects via the CIA’s unlawful rendition programme and MI5 allowed Gaddafi’s spies to carry out covert operations against dissidents on UK soil.

British intelligence agents had also allegedly been complicit in a secret policy of ‘torture by proxy’ by providing questions for feared Libyan interrogators to ask detainees.

Lawyers acting for the men have claimed in court that information illegally extracted from prisoners in Libya’s torture dungeons was central to the UK’s case for deportation.

Number 10’s extraordinary letter will raise fresh questions about the full extent of the Labour Government’s involvement in the abuse of terror suspects – and fuel speculation that responsibility for the scandal went right to Downing Street’s door.

Mr Blair has repeatedly insisted he opposes torture and has never condoned its use.

He sent the two-page letter, seen by the Mail, on April 26, 2007, the day before judges ruled the five men, all linked to the Libyan Islamic Fighting Group (LIFG), which claimed responsibility for a failed assassination attempt on Gaddafi in 1996, could not be deported.

In a letter on Downing Street-headed paper, Mr Blair thanked the despot personally for Libya’s ‘excellent co-operation’ in the controversial attempt to return the political exiles into the ruthless regime’s clutches

Political protocol dictates the Prime Minister should read the judgement before it was made public.

On April 27, the Special Immigration Appeals Commission (SIAC) blocked the deportation saying a Memorandum of Understanding signed by Britain and Libya to safeguard the protection of returning dissidents was worthless.

Gaddafi was ‘unpredictable’ and would ignore it, they said. They also expressed concern that a so-called independent board set up to monitor deportees’ treatment was to be run by Gaddafi’s son Saif and, therefore, there was a ‘real risk’ of them being ill-treated, including being beaten, hung from hooks on the wall, shackled and given electric shocks.

Mr Blair’s letter of apology began with the handwritten words ‘Dear Mu’ammar’, then continued in type: ‘I trust that you, and your family, are well.’

The letter, sent on official Downing Street-headed paper, was posted following a period in which Britain colluded with Libya to hand over terror suspects via the CIA’s unlawful rendition programme

Report: How the story was covered in yesterday's Daily Mail. Mr Blair has repeatedly insisted he opposes torture and has never condoned its use

Referring to the failed legal bid, he wrote: ‘With regret, I should let you know that the British Government has not been successful in its recent court case here involving deportation to Libya. I am very disappointed at the Court’s decision.’

Mentioning the worryingly close relationship between Britain and Libya, he said: ‘I believe that it is essential that this decision is not allowed to undermine the effective bilateral co-operation which has developed between the United Kingdom and Libya in recent years.’

He added: ‘Finally, I would like to add a personal word of thanks for your assistance in the matter of deportation. That support – and the excellent co-operation of your officials with their British colleagues – is a tribute to the strength of the bilateral relationship which has grown up between the United Kingdom and Libya.’

At the bottom of the letter, which is headed with the Downing Street seal, he hand-wrote: ‘Best wishes, Yours ever, Tony. ‘

Mr Blair’s (pictured left leaving the Houses of Parliament last week) letter of apology began with the handwritten words ‘Dear Mu’ammar’, then continued in type: ‘I trust that you, and your family, are well'

On the same day, Sir Nigel Sheinwald, Mr Blair’s foreign policy adviser, sent a rueful letter to Ambassador Abdulati Obidi, a key Gaddafi aide, apologising for the ‘very disappointing’ decision.

Criticising the court’s assessment of the regime’s brutality, he said: ‘Unfortunately, some material in the judgement will make uncomfortable reading for the Libyan authorities.

‘We regret this very much, not least in the view of the full co-operation you have given us so promptly and consistently on this issue.’

‘In particular, during the case, lawyers for the men referred to public statements made by the Leader of the Revolution.’ Gaddafi routinely referred to dissidents in exile as ‘stray dogs’. Sir Nigel added: ‘This led unavoidably to debate about the position and role of the leader.’

Last night FRI critics condemned the letter.

Sir Nigel Sheinwald, Mr Blair’s foreign policy adviser, sent a rueful letter to a key Gaddafi aide, apologising for the ‘very disappointing’ decision

Allan Hogarth, Amnesty International UK’s head of government affairs, said: ‘Our government should never have been trying to deport men back to Gaddafi-run Libya when there was a clear risk they’d end up in one of the country’s torture dungeons.

‘Rather than cosying up to Gaddafi like this, Tony Blair should have held firm to the principle that people should not be bundled onto planes and delivered into the hands of their torturers.’

Liberal Democrat MP Norman Baker said: ‘This is ghastly. The more revelations that come out about Tony Blair’s premiership, the more distasteful it seems. He seems to have no regard for basic human rights, civil values or morality.

‘How can he live with himself? I am ashamed that the UK could apologise for not sending people to a country where they would almost certainly be imprisoned and tortured.’

Cori Crider, a director at human rights charity Reprieve, said: ’Tony Blair must now urgently explain whether he knew the ‘cooperation’ mentioned in this fawning message involved kidnap, rendition and torture by his government. Thankfully, Britain today is not Gaddafi’s Libya – not even former Prime Ministers are above the law.’

Britain sought to bring Libya, responsible for the Lockerbie bombing and murdering policewoman Yvonne Fletcher, out of the international deep-freeze in the wake of the 9/11 attacks in 2001 to help tackle Muslim extremists.

In return, Gaddafi hoped intelligence sharing would help him round up and imprison Libyans who were living in exile in the UK. To do this, he played up links between the LIFG and Al Qaeda.

In February 2004, Libya wrote to Interpol with a list of 130 dissidents, including the five in Britain. A crackdown began the following month after Mr Blair cosied up to the tyrant as part of the infamous ‘deal in the desert’.

Over the next 12 months, British spies sent ‘detailed dossiers’ of questions about the men to Tripoli authorising regime henchmen to put them to detainees allegedly under torture.

Following the July 7 bombings in London, which killed 52, the men were arrested and told they would be deported as ‘threats to national security’, even though they were innocent of the atrocity.

Liberal Democrat MP Norman Baker described the revelations as 'ghastly' and added that he is 'ashamed'

But after spending nearly two years in detention, immigration judges ruled they could not be deported because they would be ill-treated.

A spokesman for Tony Blair said: ‘For the avoidance of doubt, Tony Blair has always been opposed to the use of torture; has always said so publicly and privately; has never condoned its use and – as is shown by internal Government documentation already made public – thinks it is totally unacceptable.