David Cameron has raised the prospect that computer hacker Gary McKinnon could serve some of any US-imposed sentence in a British jail after raising the issue with US president Barack Obama at the White House.
He said it was "one potential outcome" of senior-level talks between Britain and the US over the fate of Mr McKinnon, who broke into top secret US military computers.
The Prime Minister told BBC Radio 5 Live that the Government had been working with the US ambassador on options "where perhaps some of the (sentence) if there is a prison sentence - is served in a British prison".
"That is one potential outcome and I'll be working very hard to make sure that these things are discussed between the two governments and if we can reach a settlement then all to the good.
"I don't want to make a prediction because there are many difficult issues that have to be worked through."
Both Mr Cameron and Deputy Prime Minister Nick Clegg have publicly condemned plans to extradite Mr McKinnon to the US - where he faces up to 60 years in jail.
Last year, Mr Cameron said that if Mr McKinnon, 43, had questions to answer there was "a clear argument to be made that he should answer them in a British court".
Speaking at a White House press conference alongside President Obama, Mr Cameron said: "Clearly there is a discussion going on between the British and the Americans about this but I don't want to prejudice those discussions,
"We completely understand that Gary McKinnon stands accused of a very important and significant crime in terms of hacking into vital databases and nobody denies that is an important crime that has to be considered.
"I have had conversations with the US ambassador as well as raising it today with the president about this issue, and I hope a way through can be found."