"It would be like committing suicide. As soon as I step out of the Green Zone I would be walking around Baghdad with the word 'target' across my forehead." This is the fate awaiting Zyad al-Saadon, an Iraqi who has lived in Britain for 35 years. He faces deportation under the government programme for forced removal of failed asylum-seekers and foreign convicts.

He has been offered £500 from the British embassy in Baghdad if he goes voluntarily but nothing if his removal is enforced.

"They must be bloody mad if they think after all this time in Britain, a country I consider home, I'm going to voluntarily walk out of here [Dover immigration removal centre] and on to a plane to Baghdad. I'd be dead in days."

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Mr Saadon, 54, is one of dozens of Iraqis facing removal to Iraq, despite making claims to residency or asylum in the United Kingdom. The Government argues that under the strict terms of immigration law there is no "internal armed conflict" in Iraq and encourages those in detention to voluntary return to Baghdad and Basra.

Home Office officials claim that Mr Saadon, who says he has been granted indefinite leave to remain in the United Kingdom, cannot prove that he has lived in Britain since the 1970s. But The Independent has obtained a copy of his marriage certificate, which shows he married Doreen Gardiner, the daughter of a Kent refuse collector, in Folkestone on 3 January 1976.

Mr Saadon, the father of two adult children living in Britain, claims to be the victim of a harsh removal programme that aims to increase deportations at any cost in order to meet asylum removal targets. Foreign nationals with convictions are seen as easy targets for removal as their cases rarely attract public concern. While the Government works out how to forcibly return Iraqis back to central and southern parts of the country, many are being held in detention long after their prison sentences have expired. In some cases this can mean more than two years' additional detention.

Mr Saadon says he came to Britain in 1973 when his father sent him to a Kent college to study engineering. Three years later he began a civil engineering degree at Swansea University. But soon after moving to Folkestone in Kent, where he worked as a manager at an amusement arcade, his marriage collapsed.

"I began to struggle to keep my life together and started taking drugs, mostly heroin. I fell in with bad people and committed crime to feed my habit. I was down and out and for a long time I begged all over Kent."

On 8 April 2004 he was convicted at Maidstone Crown Court for selling crack cocaine to an undercover police officer and was sentenced to five years' imprisonment, which he completed in July last year. It was then that Mr Saadon learnt that the Home Office had ordered his deportation to Iraq.

"It is unbelievable. I told them that I came here at the beginning of the 1970s and have raised a family but the Home Office don't believe me. They have told me I must go back to Iraq where I have no family and where I don't know anyone. I'm British now and I'm a British problem, not an Iraqi one."

The chief executive of the UK Border Agency, Lin Homer, said: "Those who come to the UK and break our rules, and are judged to be a threat to the public, will not be tolerated. Foreign nationals must obey the laws of this country in the same way as everybody else. Those who have committed criminal offences here are subject to the same legal processes as anyone else in the UK.

"Anyone breaking the law, irrespective of whether they are a British citizen or a foreign national, can expect prosecution and, where appropriate, a custodial sentence. We have also made it perfectly clear that we will seek to deport foreign nationals who have committed a serious crime in the UK. The UK Border Agency only enforces the return of individuals where we and the independent courts are satisfied they are not in need of international protection."

Mr Saadon has spent nearly a year in detention at Dover immigration removal centre where he is awaiting deportation to Baghdad. Staff say he is now clean from drugs and he has become a trusted detainee who works as an interpreter.

For Mr Saadon, the offer of a voluntary return to Iraq is not one he finds attractive: "All I want to do to find my children, who I have lost contact with, and live the remainder of my life in peace. If they send me to Baghdad they might as well give me the bullet now and I'll save them the trouble."