If Rageh Omaar was the face of the Gulf War, then Robert Peston, the BBC's business editor, has become the poster boy of the financial crisis. Whereas Mr Omaar became known as the Scud Stud, Mr Peston has yet to earn an appropriate sobriquet, but for the moment he possesses the power to move the London stock market. His blog is keenly followed in the City - remarkable, really, given that traders have little to do with the BBC most of the time - and bankers send circulars summarising his latest posting for those unable to type in the web address for themselves.

The belief in the City is that Mr Peston is so close to the Government that anything he predicts will definitely come to pass - a faith that emerged after he revealed that Lloyds TSB was to buy HBOS several hours before the deal broke. That story was so accurate that the FSA is conducting an insider-dealing investigation, as HBOS shares ramped up minutes before the journalist broke his story. No wonder, too, that RBS shares obediently tumbled on Tuesday after Mr Peston predicted that the bank would need £15 billion of new capital from taxpayers (although the assumption that the new investment would dilute existing stockholders appears to have been incorrect).

The perceived power of Mr Peston has inevitably provoked some hostile press, although much of it feels as if it has been prompted by a mixture of envy and muckraking. Good financial journalism ought to move markets; what is more troubling is the communication gap between accurate leaks and a factual update of the market.

Where the information is coming from is unclear, and Mr Peston is hardly likely to tell. A flurry of finger-pointing as ministers blamed the Opposition, or even the stricken banks for spilling the beans on briefings, nicely confused the picture. What is clear, though, is that the old lobby practice of slipping out financial information before an announcement is highly risky. As soon as, for example, there are hints that the Government is willing to bail out banks, ministers might as well write the cheque - because the market will mark down the shares until the cash comes.

For all our sakes, then, we should hope that the BBC journalist or his sources continue to get the story right. Last week Apple's stock tumbled after a blogger, on a site linked to CNN, posted an untrue report saying that Steve Jobs had suffered a heart attack. US authorities are investigating the posting. Last month, Google News picked up a six-year-old story that United Airlines had filed for bankruptcy. The report was assumed, briefly, to be current, and United's shares tumbled before the error was corrected.

In this febrile environment, scoops can have tremendous impact. Readers, though, ought to bear in mind that a blog, or even Google, is not necessarily as reliable as the man on the telly.

Channel 4

Channel 4 is in trouble with its plans to move into digital radio. It wanted to launch three new stations, and won the right to run a “multiplex”, a block of frequencies that allowed it to support six more from elsewhere. With a slump in radio advertising, launching stations at this time looks foolish. And given that Channel 4 is talking about a wider funding deficit, the digital radio plan borders on foolhardy.

Talks last week that aimed at merging Channel 4's multiplex with the original commercial frequency block held by Global Radio failed. There seems to be too many parties to please. It might make an agreeably chaotic phone-in, but it is otherwise hardly good news for the commercial radio business.

Nor, frankly, is it obvious why Britain needs more radio stations, when fewer, better stations might be the answer. Why did Ofcom think it smart to insist on licensing a third national multiplex - in addition to the ones owned by GCap Media, now Global Radio, and the BBC? There was no shortage of radio stations already in FM - remember there are regional digital multiplexes, too. However, there seemed to be a collective enthusiasm for “public service competition” to the BBC from a new Channel 4 radio, a nice enough theory, but one without proven value to listeners. Today, on Radio 4, is brilliant precisely because it has no competition. After all, which politicians want two long radio interviews before 8.30am when they could be on GMTV instead?

It would have been better if Channel 4 had started modestly - launching a single station to see whether its BBC-lite concept was viable. Instead, it insisted on chasing a multiplex in pursuit of the rental revenues from partner stations to minimise its risk - presumably because it was unsure that its three stations would become profitable quickly enough. But if they were not to become profitable in good time, why launch them at all?

Nor did the broadcaster win friends by describing to anyone who cared to listen that the rest of commercial radio was rubbish (in carefully chosen words). That, though, was then. Channel 4's best option now might be to hand back that multiplex and sound a retreat. After all, listeners won't miss something they could never hear.

dan.sabbagh@thetimes.co.uk

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