One of the longest feuds in British politics ended yesterday when Gordon Brown endorsed Ken Livingstone's bid to be re-elected as Mayor of London.
Eight years ago, Mr Brown warned it would be a disaster for the capital if Mr Livingstone got the post. Mr Livingstone responded by accusing Mr Brown of not being up to the job as Chancellor and calling for his resignation.
But the men buried their differences yesterday in an attempt to see off the challenge of Boris Johnson, the Conservative candidate, for the mayoralty.
The pair smiled and shook hands for the camera as Mr Brown accompanied his former foe on the campaign trail.
The Prime Minister did not deny there had been tensions between them, but preferred to lavish compliments on Mr Livingstone's performance as mayor since 2000.
Mr Brown said: "He is an inspirational figure in London, a crusading mayor and one who has made a huge difference." He praised Mr Livingstone for his "lifelong commitment" to the capital, saying it was his understanding of the city which had delivered so much for Londoners. They joined forces after a poll showed Mr Johnson with a 12-point lead over the current Mayor. Victory for the Tories on 1 May would be a serious blow for Labour and fuel speculation that David Cameron is on course for Downing Street at the next election.
Labour sources are also worried that a bad result would further erode its support in marginal parliamentary seats in and around the capital. They fear that Mr Livingstone's popularity is being diminished by controversy over the use of public funds by the London Development Agency, anger over Post Office closures and gloom over the state of the economy.
Labour is putting the £16bn Crossrail project, linking the east and west of the city, at the heart of its appeal to voters. It claims fares would have to rise if Mr Johnson became Mayor.
Mr Livingstone said: "I am not being in the slightest alarmist when I say that if Crossrail were to go wrong you are looking at 30 per cent increases in fares and doubling of supplementary business rates."
Until yesterday Mr Brown had barely seemed able to utter Mr Livingstone's name, simply referring to him as "the Mayor" in the Commons recently. Mr Brown is expected to rejoin Mr Livingstone for further campaigning as polling day approaches.