A Russian scientist who was released and flown to Britain after a spy swap between his country and the United States - the biggest since the end of the Cold War - has told the BBC that his wish is to return home. In his first UK interview since his release, Igor Sutyagin spoke to the BBC's Diplomatic correspondent Bridget Kendall.
Looking thin and wan in clothes several sizes too big for him, Igor Sutyagin said he still found the pace of life in Britain bewildering.
After being plucked last month from a Russian prison camp near the Arctic Circle, he was days later on a plane to Vienna, one of four being sent to the West in return for Russian agents who confessed to being part of a secret spy ring living undercover in the USA.
But Mr Sutyagin insists he is not in the same category as the spies he was being swapped for, and was highly uncomfortable about being part of the espionage exchange.
"I was really very unhappy and very sad about that," he said. "I definitely do not want to leave Russia and that was not the most desirable thing for me. I definitely wanted to be released. I definitely wanted to be free. But I wanted to be free on just grounds."
An arms control researcher at a well respected Moscow think tank, he says he came under suspicion after he attended a security conference in the UK in the 1990s.
He was approached by members of a firm who asked him to do some research for them on the investment climate in Russia. Mr Sutyagin says they were interested in commercial not military information and everything he gave them came from open sources.
From his knapsack he pulled out a sheaf of well-worn cuttings, carefully kept in plastic sheets: an article from the Washington Post, and the report of a military press conference from the Russian military paper the Red Star. He had circled relevant passages.
"See," he said," this is the same information which I was convicted of passing on as secrets. But it's published and open for all to see."
In late 1999, just after Vladimir Putin had taken over as prime minister, he was called in for talks by the FSB, the Russian internal intelligence service. "And then," he says with a wry smile, "I disappeared."
He was arrested and charged with allegedly passing Russian military secrets to Western intelligence agents. After five years in detention and three trials later he was finally convicted and sentenced to 15 years in 2004.
He plays down the hardships of being in jail, saying he does not want to complain, and insisting that life on the inside is not always as bad as it is painted. Even so, he admits that at times in prison he was afraid.
"It could be very dangerous. There are many, many things which can happen to you in prison from both the administration and from criminal inmates. It's a very dangerous place."
Throughout his 11 years in detention, in a succession of Russian jails and labour camps, Mr Sutyagin continued to protest his innocence. Amnesty International took up his cause.
When the security services allowed, letters and cards would arrive from Amnesty supporters, which both gave him hope he had not been forgotten and made camp guards aware he was an unusual prisoner whose case had been taken up by the outside world.
"There were lots of people who supported me and who sent me letters, words of their support to the camps, both from Russia and from outside. The people of Amnesty International sent me literally thousands of letters. It was very serious support for me and I think it is very serious support for everybody who like me is behind bars now."
Mr Sutyagin says his release last month came as a shock. It was only after he was transferred from his northern camp to the infamous Lefortovo prison in Moscow that he learnt he was about to be part of an international spy swap.
He says at first he refused when ordered to sign a confession, in case it was seen as an admission of guilt. He only agreed because of his family and because he was told that otherwise the entire exchange of prisoners would be cancelled and he did not want to be the cause of anyone being kept locked up.
But now in Britain, staying with friends and with a six month work visa in his passport, his journey from prison to freedom is bittersweet. Astonishingly, after all he has been through, he would rather be back in Russia.
"There is a strong difference between a country and a state," he told me. "My country is Russia and I don't blame Russia for my imprisonment. That is why I want to come back to Russia. Not to the Russian state. I want to come back to my country, my nation."
And as for fears that he could face the same thing all over again, a new arrest, he said he was aware of the danger, but it did not change his mind.
"Why do British sailors dream of the white cliffs of Dover when they are far away?" he asked, with a typically Russian whimsical flourish. "I dreamt of Moscow, or more precisely of my town outside Moscow. Those are my white cliffs."