By Gordon Corera
Binyam Mohamed's case is a sensitive one for both US and UK governments
The US/UK intelligence-sharing relationship is incredibly close and has been all the way back to World War II.
It is arguably at the centre of what is known as the "special relationship". Much - but not all - material is shared.
In some cases, like the relationship between the GCHQ intelligence centre in Cheltenham and America's National Security Agency (NSA), the two countries' listening agencies, the work is very intimate.
The US is by far the bigger partner. Its intelligence budgets dwarfs that of the UK, making its products highly valuable in London, although in certain areas the UK does provide important contributions.
Just how close the relationship is can be seen by the fact that a representative of the US intelligence community (normally the CIA) often sits in on some meetings of Britain's Joint Intelligence Committee representing Washington.
But while this liaison relationship is crucially important, all intelligence agencies worry about their secrets being made public by another partner, whether accidentally or through some kind of legal or legislative process.
Ending intelligence co-operation between the US and UK is almost unthinkable, but a threat to rethink how that relationship works and what exactly is shared could be serious.
British officials are adamant that no explicit threats were made but do say that the US expressed very real concerns about what the disclosure of US information relating to rendition and the case of Binyam Mohamed would mean.
This case is highly sensitive since it involves not only allegations of torture as part of the CIA's extraordinary rendition programme but also allegations of UK complicity in this by providing questions to ask Mohamed during his detention.
A problem for the Obama administration is that it is walking a fine line when it comes to disclosures about controversial intelligence practises during the Bush years.
President Barack Obama has made great play by drawing a line under the past, calling for the closure of Guantanamo and an end to torture.
But he also has been careful not to rule out the continued use of some forms of rendition which do not involve torture.
He also does not want to alienate and demoralise the intelligence community too much by launching difficult, intrusive investigations into what happened during the Bush years.
So a decision whether or not to allow the UK to make details of Mohamed's treatment public has many complications and sensitivities on both sides of the Atlantic.