The initiative is said to be the brainchild of Downing Street chief of strategy Stephen Carter and is intended to 'humanise' the Prime Minister as his popularity continues to wane.

'Carter thought it was a good idea to have Brown call people personally,' said one insider. 'Carter will choose a letter or email at random, have one of his team at Number 10 prepare a res­ponse, then get Brown to call.'

The move is an attempt to spread positive word of mouth for the PM, especially in the ­regions, as Brown faces an increasingly negative media.

However, one of the first phone calls backfired spectacularly, according to one anecdote told to PRWeek.

'Brown made a phone call at 6am, without thinking,' said a well-placed Labour source. 'Luckily the person he called was a shift worker, so he was awake.'

The source added: 'Carter's idea is well meaning, but it's not working. Improving Brown's ­image through PR is now being looked at as a lost cause.'

Downing Street declined to comment on the story.

Meanwhile, a survey of senior PR professionals by the PRCA reveals that only 15 per cent bel­ieve Brown can significantly ­improve his reputation by strengthening his communications team. Some 42 per cent said it would have no effect.