A retired British businessman will be escorted by US marshals to America today after failing in his two-year battle against extradition.
Christopher Tappin, who is accused of conspiring to sell components for Iranian missiles, will meet the marshals at Heathrow police station and be taken to the US where he could face 35 years in jail.
He told the BBC: "I am 65 years old now. If I was to serve 35 years than I would be 100 by the time I came back.
"There aren't many people who reach 100 so I have to be philosophical about these things, that I may never come home to my own country again."
The 65-year-old golf enthusiast is the latest Briton to fight and lose an extradition battle with the US and his case increases pressure on the Government to review the arrangements.
David Cameron said on Wednesday that the government would carry out a "proper, sober and thoughtful" review.
But the Prime Minister added that it was important to remember that extradition treaties "show respect to each other's judicial processes and make sure that people who are accused of crimes are tried for those crimes".
"Britain can benefit from that as well," he said.
An independent review of the UK's extradition arrangements by retired Court of Appeal judge Sir Scott Baker last year found that the current treaty between the US and the UK was both balanced and fair.
But critics claim it is one-sided, with MPs, peers and campaigners all calling for reform.
Jago Russell, the chief executive of Fair Trials International, said: "After years of talk about extradition reform, and countless cases of injustice, still nothing has been done.
"It is high time the government brings forward concrete proposals to build much-needed safeguards into our laws."
Tappin denies attempting to sell batteries for surface-to-air missiles which were to be shipped from the US to Tehran via the Netherlands.
He has said that for justice to be done, he should be tried by a jury of his peers in the UK, not a jury 3,000 miles away who do not share a common cultural background.
But magistrates and the High Court backed his extradition, and he exhausted his appeal options earlier this month when a last-ditch plea to
the European Court of Human Rights was rejected.
Tappin, from Orpington, Kent, has claimed he was the victim of entrapment in a "sting" organised by US government agents.