Boris's £300,000 campaign invested in champagne and a Castro outfit

The money, which is £100,000 less than permitted, was also spent on 1.5 million leaflets, the disposal of 260kg of rubbish and fundraising.

A breakdown of campaign expenses between 18 March and the election on 1 May shows the spending habits of mayoral candidates Mr Johnson and Ken Livingstone.

Neither spent the maximum £420,000 permitted but records show Mr Livingstone outspent Mr Johnson by £85,000 in his unsuccessful bid to secure a third term.

While the successful candidate raised £1.5 million he spent £324,034 on the final push. He invested most of the cash establishing himself as a contender at the start of the year.

Mr Livingstone preferred to spend his money on advertising and polling, while Mr Johnson's total bill for salaries, hotels and office space was more than four times that of team Livingstone, with the Tory candidate spending £94,485 on staff and £45,330 on accommodation.

Mr Johnson's team also put their efforts into wooing financial support with several lavish events for donors, including one that consumed 48 bottles of Renard-Barnier champagne.

But the tactic paid off, with three Johnson supporters giving more than £1,000 of wine from their own cellars for other events. In his official return to electoral authorities, Mr Johnson named almost 250 donors who gave between £100 and £25,000.

Instead of fundraising Mr Livingstone relied on the support of trade unions.

While the former mayor refused to disclose details of his donations, which were funnelled through the Labour Party, Mr Johnson has continued to publish a list of all gifts on the City Hall website.

These include a £25 cycle helmet that was presented to him by Labour Assembly member Val Shawcross at his first Question Time.