BBC business editor Robert Peston has become famous for breaking big stories about the credit crunch – and infamous for revelling in bad news.  

His Peston's Picks blogpost today about Marks & Spencer's trading update was a classic:

"Here's the ghastly bit: overall UK sales were down 3.4%…"

 He described M&S's story as "pretty dire". 

I'd say that a fall in sales of under 10% was pretty impressive in the current economic climate. Car makers would love that kind of resilience. We're all cutting back, just in case things get serious, so sales are bound to fall. We should therefore be sanguine when companies fail to report the kind of bumper results and profits of recent years.

That's not to say Preston is always wrong. A year ago, I defended his scoop about Northern Rock's rescue. That story was totally justified, and reflected the bank's disastrous management failure, rather than causing its demise. But as the credit crunch has turned into recession, Peston's rush to comment has become his weakness. The BBC may be happy with Peston's Stakhanovite productivity, but the rest of us question his 'we're doomed' approach. Peston's bosses should tell him to restrain his glee.

DISCLOSURE: I am a former head of PR for M&S Money, though I was never an M&S employee.