Last summer, a senior official at the British Embassy in Washington also telephoned Abramson at the New York Times to request the return of Snowden data – a request Abramson has said she denied.

“We were made aware that the NYT might be in possession of a large number of stolen, highly classified documents,” said a British official who declined to be named. “Would it be unreasonable of us to ask for them back?”

A spokesman at No. 10 Downing Street declined to comment for this article, instead referring to published comments by the prime minister. In October, Cameron, a Conservative, took a thinly veiled swipe at the left-leaning Guardian: “I will back the work [security services] do and I will criticize those that make public some of the techniques they use because that is helping our enemies.”

The Guardian has also become the target of a number of other Conservative lawmakers. One, Julian Smith, has pointedly sought information from the paper on whether it willfully shipped the names of British secret service agents overseas — an act that could be punishable by law in Britain.

“I’ve got numerous concerns about how the Guardian has conducted itself,” Smith said. “I believe in freedom of the press and the Guardian’s right to write about these leaks, but there also needs to be a sense of moral responsibility.”

Asked in an e-mail whether the Guardian sent data with names of British agents overseas, Rusbridger did not answer directly. He said: “It’s been apparent to any casual reader since early June that the Snowden documents contain names of some employees of the NSA and GCHQ. We have had no approaches from government or agencies in relation to any names. We have published no names, nor lost control of any material.”