The Sunday Times responded to allegations that it used ‘blagging’ techniques to find out details of Gordon Brown’s building society account and property dealings.

The Guardian reported that an agent working on behalf of the Sunday Times tricked staff at a law firm to hand over details of Brown’s private file.

And it also alleged that in 2000 someone acting on behalf of the paper posed as Brown to trick staff at an Abbey National call centre into revealing details of his bank account.

The Sunday Times said in a statement: “We were told that Mr Brown had bought a flat cheaper than any normal valuation and that he obtained it through a company in which Geoffrey Robinson, a close ally, had been a director.

“We had reasonable grounds to investigate this matter and followed the  PCC  code on using subterfuge.

“We believe no law was broken in the process of this investigation, and contrary to Mr Brown’s assertion, no criminal was used and the story was published giving all sides a fair hearing.

“We also note that Allen & Overy, the law firm, have denied they handed over any details about the purchase of the property and had nothing to do with it.”

Stablemate, The Sun has also denied accessing the medical files of Brown's son, Fraser, who suffers from cystic fibrosis.