The Tory and Lib Dem candidates, Steve Norris and Susan Kramer have also seen their support grow from 11% to 13% and 6% to 8% respectively.

Around a third of those interviewed for the survey of 1,005 people were quizzed after it was announced that Mr Livingstone had fallen foul of parliamentary rules on declaring his earnings outside Parliament.

Their results on Mr Livingstone's trustworthiness showed little difference from the rest of those polled with the Brent East MP considered honest by 62% and dishonest by 18%.

Consistent lead

The first opinion poll conducted after Mr Livingstone's declaration to stand at the beginning of March by the Guardian/ICM, suggested he would poll 68% of the vote, leaving Mr Dobson on 13%.

The survey of 1,003 adults across London also suggested, Mr Livingstone would receive the support of 75% of Labour voters, 70% of Liberal Democrat supporters and 48% of Conservative voters - far higher than support for their official candidates.

This reflects the finding of a poll, also carried out by ICM, for London's Evening Standard newspaper after the Labour selection result was declared in February.

Carried out immediately after the announcement of Labour's candidate, 61% of those questioned said Mr Livingstone should go it alone while 22% said he should accept the result.

When asked who they would back in a four-way race, 50% of Londoners choose Mr Livingstone, while only 22% favoured Mr Dobson.

Tory candidate Steve Norris came third with 15% and Liberal Democrat Susan Kramer took just 8%.

Although the poll was carried out in the aftermath of the Labour contest, for the Dobson campaign it is worryingly similar to polls carried out along the same lines last autumn.

Another ICM poll conducted for the Guardian had an independent Livingstone running on 43% with Dobson trailing on 23%.

Statistics giving the Brent East MP a significant lead date back to last October, shortly after Mr Dobson entered the race. They put the Holborn and St Pancras MP on 18% against an independent Livingstone on 34%.