Robert Peston, thorn in Darling’s side

Described variously as a brilliant journalist, "a market menace" and the man with the most annoying delivery on television, there is no denying who is the greatest thorn in Chancellor Alistair Darling's side today - Robert Peston (pictured), the BBC's business editor.

The government's £50bn plan to rescue the banking sector announced early this morning had to be rushed into place because - once again - Peston had produced a scoop that set the cat among the pigeons. In his BBC blog posted early on Tuesday, Peston announced that at a meeting the previous day "a gang of three of Barclays, RBS and Lloyds TSB told Darling to pull his finger out and finalise whatever it is he's eventually prepared to offer on taxpayers' behalf".

As a result, bank share prices duly tumbled yesterday. And while Peston was accused by Treasury officials and the banks themselves of spooking the markets by over-hyping the bankers' fears, the government was forced into pulling forward its rescue plan.

In City circles, 48-year-old Peston is rapidly becoming known as "the man who moves markets". His recent string of scoops began last September when he disclosed that Northern Rock was seeking emergency funding from the Bank of England. Some claimed that the subsequent run on the bank was partly attributable to Peston breaking the story.

Last month questions were asked again when it turned out that speculators bought millions of HBOS shares in the moments leading up to Peston's report that Lloyds TSB was engaged in takeover talks.

While the BBC man's star rises - searches for 'Robert Peston' on Google have shot up in the past four weeks, according to Webuser - some media watchers wonder whether Peston's scoops could get the better of him. A source told The First Post: "Alastair Campbell famously left Downing Street when he 'became the story'. Peston needs to be careful he doesn't meet the same fate."

Peston and Campbell, incidentally, are old foes: when Peston was political editor of the Financial Times in the 1990s Campbell would regularly regularly mimick Peston's habit of flicking back his hair and once responded to a difficult question with the words: "Another question from the Peston school of smartarse journalism."

Whether Peston's latest scoop came from within the banking sector or from his contacts inside government, is a matter of conjecture. His friendships inside Number Ten date back to his 2005 book Brown's Britain, written before he joined the BBC, which told the story of the Brown-Blair power struggle from Brown's side. Peston was given "unprecedented access to Gordon Brown and his friends and colleagues" according to the publishers.