Claims the US has secretly flown terror suspects through the UK will eventually "fall away" due to lack of evidence, says Foreign Secretary Jack Straw.
Allegations on rendition flights continue
Mr Straw told MPs somebody would have seen something if prisoners really were being flown through UK bases.
But nobody had come forward, nor had there been a single "bit of paper" leaked from the US authorities to suggest the practice was going on.
The current US government had not asked the UK about moving suspects, he said.
Mr Straw was giving evidence to the Commons foreign affairs committee, which has said the UK government was too slow to start investigating claims about so-called extraordinary rendition flights.
He said that if CIA planes had flown through UK territory and airspace, it did not follow that they had been carrying prisoners.
"If there had been people who had been rendered in this day, I think it is a fair bet that somebody would have spotted this," said Mr Straw.
He predicted the claims would continue for a period despite the lack of evidence but then fall away.
US Secretary of State Condoleezza Rice has said suspects are flown abroad for interrogation but denies torture is used.