Livingstone hints at run in 2012

Mr Livingstone said Tony Blair had been wrong to rule out re-election

Labour's London Mayor Ken Livingstone has refused to rule out running for a fourth term in 2012 if he wins a third election next month.

Speaking on BBC Radio 4's World at One, he said it would be a "mistake" to do so, as it could "weaken" him in office.

Opinion polls suggest Mr Livingstone is facing a strong challenge from Boris Johnson, with recent surveys putting the Conservative challenger ahead.

There are 10 candidates for the London election on 1 May.

Clinton

When asked, Mr Livingstone refused to rule out another run for the job in 2012, adding: "One of the big mistakes Tony Blair made was to go into an election saying he would not seek re-election; it weakened him."

He added that US President Bill Clinton would have won a third term in office in 2000, had the country's constitution allowed him to run.

A Guardian/ICM survey published last week suggested Mr Johnson would get 42% of first-choice votes, compared with 41% for Mr Livingstone. Lib Dem Brian Paddick was third on 10%.

With the first and second choices of the sample of 1,002 adults counted, Mr Johnson got 51% and Mr Livingstone 49%.

But an online survey of 1,003 voters, published in the Evening Standard on Monday, gives Mr Johnson 49% of first-choice votes and Mr Livingstone 36%.

Liberal Democrat Brian Paddick polled 10% and Green nominee Sian Berry 2%.

Mr Livingstone's spokeswoman said YouGov's polling technique was flawed, and a formal complaint had been lodged.