The CIA station in London is at the center of a bitter fight between different branches of the US intelligence community in Washington DC.

For years, the CIA has had the right to appoint the station chief who runs US intelligence operations in London and liaises with MI6 and GCHQ. Now, the National Security Agency is arguing that they and not the CIA should run intelligence operations in the UK because they have more people on the ground and the work they do has far greater value to both countries.

NSA have found useful allies in both Admiral Denny Blair, the Director of National Intelligence and General Jim Jones, the National Security Adviser who have been very receptive to the argument that intelligence form should follow function and reflect the realities of the 21st century.

Last month, Blair wrote a memo to US intelligence chiefs saying that in future the DNI would appoint Heads of Stations overseas. It was a clear directive from the man who runs all US intelligence and is appointed by the President and Congress to do so. However, Leon Panetta, who heads the CIA and is the former Chief of Staff to President Bill Clinton, wrote his own letter to top CIA officials saying they could disregard Blair’s note.

Panetta is a famous Washington bruiser and is well known for his take no prisoners style but such a confrontation has infuriated Blair who sees it as a direct challenge to his authority and battle has been joined. For once, Panetta may have misjudged the political winds as Congress is pushing hard for real intelligence reform and the CIA has fewer friends and less influence on Capitol Hill these days.

It is no coincidence that those pushing for change in the Obama administration have a military background and that the NSA is run by one of their own, General Keith Alexander. It’s also true that for decades NSA has chafed under CIA’s apparent seniority and the two agencies have been arch rivals for generations. As recently as the Bush administration a major joint operation between CIA and NSA which all involved agreed was vital to the future of US security was stopped after a senior CIA official refused to implement the project which he thought gave unnecessary influence to NSA.

The information revolution has placed further strains on the relationship. Twenty years ago, there was a clearer division of labour with NSA intercepting data on the move (email, faxes, phone calls) while the CIA targeted data at rest (documents, burglaring buildings). But recently the CIA has made a major push into the data gathering business arguing that the ones and zeros of the computer age are data and thus are fair game whether at rest or on the move.

There are thousands of Americans based in Britain who work for NSA and work closely with GCHQ. By comparison, the CIA station, based in the US Embassy in Grosvenor Square, is important but a mere shadow of the NSA’s presence. Reality on the ground suggests that NSA will win this fight.