It's all a bit more sinister than that
Name me a politician who does not have some shady financial deal in his past... I'm not one for judging, we nearly all have something to hide, it's just that the sorts of people who make proper political deals (rather than being fucked over by PFI) seem to have learned their trade at a somewhat sharper end of the business. We will always be open to shady sponsorship allegiances, since we cannot find a fair way of publicly financing political parties.
Now, give all the data to the Americans, and let's wonder why certain politicians suddenly appear slavishly intent of following the CIA line, I'm looking at you Tony.
I'm no great conspiracy theorist, but its been on record that the American spooks consider the commercial success of US business an equal priority to the defense (sic) of the nation. There is no way that this information will not be mined by the best brains they have for any potentially useful "Intel".
Knowledge is power, only a complete fuckwit cretin would hand it all over to a potential adversary.