There may have been the "odd case" where British agents were aware of torture being carried out by the CIA, a former Security Minister said.
Admiral Lord West said torture was "abhorrent" and was not used by the British because "we have to be whiter than white" in the battle against international terrorists.
But the Labour former minister, who was previously chief of defence intelligence, acknowledged it was possible individual agents in the field knew what US counterparts were doing to detainees.
Lord West said that 10 or 15 years ago it was not clear to British spies "as to exactly what their position was in regards to these things".
But he told the BBC: "That is now made very, very clear. It started to be made clear by the last government that they must not be involved at all or even around when this is going on.
"Looking back historically, if you are an agent embedded in some foreign country and this was going on, it was quite difficult for them to extricate themselves even though they weren't implementing that torture.
"So I'm sure there may be the odd case where an agent was aware what the Americans were doing, but that has now been sealed off because they are very clear now what the position is."
The former head of the Royal Navy insisted the British were not involved in torture: "These things are abhorrent. Our Government is very clear, and the British are very clear, we do not use these techniques.
"For a start, you can't guarantee getting good intelligence from it. So we don't use them, it's wrong. We have to prove that we have standards of decency that put us apart from them."
Deputy Prime Minister Nick Clegg has acknowledged a full judicial inquiry may still be required into allegations of British complicity in torture if police and parliamentary probes fail to answer key questions.
But Lord West told Sky: "I really do think it's a waste of time, what are we trying to prove? The only thing one might find is 10, 15 years ago maybe an agent or maybe two agents were aware waterboarding was going on, indeed may even have been in the same building.
"But in the last 10 years or so we have made it very clear exactly what the position is for all our agents, they know they are not allowed even to be there when anything like that happens."