Boris claims 13-point lead as Ken camp attack polling

Boris Johnson has claimed his most commanding lead yet in the race to be elected mayor of London on May 1st.

The Conservative candidate is 13 points head of the incumbent mayor according to the last YouGov poll for the Evening Standard.

However, Ken Livingstone's campaign team have continued to attack the poll's "flawed methodology" and insist Mr Livingstone is still in the race.

Today's poll shows support for Mr Johnson has risen two points over the past week to 49 per cent, while Mr Livingstone is down one point on 36 per cent.

Lib Dem candidate Brian Paddick remains unchanged on ten per cent, having peaked at 12 per cent, and the Green party's Sian Berry equally static on two per cent.

A result along these lines on May 1st would see Londoners' second preference votes become decisive in electing the next mayor of London.

Here it appears Mr Livingstone has begun to reclaim support, picking up second preferences from Liberal Democrat voters.

The Fabian Society has today written to senior Lib Dem figures, urging Mr Paddick to encourage his supporters to list the mayor as their second preference to stop Mr Johnson being elected "by the back door".

But even with second preferences taken into account, Mr Johnson is leading 54 per cent to 44 per cent.

The poll, which was taken before news broke of Mr Livingston's five children or Mr Johnson's cocaine use, contrasts with a Guardian poll last week which suggested the two candidates are virtually neck and neck.

Mr Livingstone's campaign claimed YouGov's methods underestimate the capital's substantial ethnic minority electorate and overestimates the proportion of older residents and consequently "consistently over-estimate support for the Conservatives".

A spokesman for Mr Livingstone's campaign confirmed it had lodged a complaint with the Market Research Council of Great Britain.