The US government has contributed at least £100m to the budget of the UK's GCHQ in the last three years in a bid to make sure the intelligence agency "pulls its weight", according to information revealed to the Guardian by NSA whistleblower Edward Snowden.
The paper cited a GCHQ strategy meeting in which attendees were told: "GCHQ must pull its weight and be seen to pull its weight."
It has already been revealed that the UK played a large role in American surveillance tactics, allegedly tapping Atlantic internet cables in order to keep track of web traffic, emails and phone calls originating from the European continent in an operation known as Tempora.
It said that at least £22.9m was handed to GCHQ in 2009, with a further £39.9m contributed in 2010 in a bid to assist its Mastering the Internet project.
It was also revealed that GCHQ has seen a 7,000 percent increase in the amount of mobile web traffic it is able to keep tabs on. The Guardian also alleges that GCHQ places the blame for the majority of cyber attacks against the UK squarely on China and Russia, and is now working with the NSA to create a cyber warfare strategy.
A senior Whitehall security source told the Guardian, however, that the close relationship isn't quite as co-operative as it has been portrayed. "The fact is there is a close intelligence relationship between the UK and US and a number of other countries including Australia and Canada. There's no automaticity, not everything is shared. A sentient human being takes decisions."
Edward Snowden was yesterday granted temporary asylum in Russia, sparking a diplomatic spat in which the White House said it was "extremely disappointed" with the decision.
Earlier this week the software behind the PRISM campaign was revealed, showing the full extent of the USA's surveillance methods and the alleged lack of justification required to do so.
The revelations come despite foreign secretary William Hague saying that UK citizens should have "confidence" in GHCQ, arguing its work is vital for national security.