Tory Boris Johnson, Labour's Ken Livingstone and Lib Dem Brian Paddick
By Justin Parkinson
Political reporter, BBC News
London is preparing to elect its next mayor.
Two of the most recognisable figures in UK politics - Labour's Ken Livingstone and Conservative Boris Johnson - have spent months attacking each other over issues such as crime, transport and the environment. There have also been plenty of personal criticisms.
The Liberal Democrat candidate, former Metropolitan Police commander Brian Paddick, has been weighing in too and as many as 10 others may well put their names forward.
The contest to be held on 1 May is expected to see as many people voting as take part in the Scottish Parliament elections - and far more than for the Welsh Assembly.
But, if you live outside the M25, the chances are you do not care two hoots who wins.
Should you, though?
Mr Livingstone, the incumbent, has not denied that the mayoralty amounts to a "personal fiefdom".
The winner, given a direct mandate, has a huge array of powers over things such as transport, planning, policing and economic development - all without much of the restrictive red tape encountered by other politicians.
For instance, the congestion charge - Mr Livingstone's best known and most controversial change - would probably still bejust a plan if there was no mayor.
But, with 11 weeks to go until polling day, what is the significance of the election for the rest of the UK?
Peter Kellner, president of the YouGov research group, thinks the result will send a strong message to parties as they contemplate strategies for the next general election, possibly in 2009.
He said: "I think the national implication is that if Labour's Ken Livingstone wins then Labour can say 'We've held off the Conservatives'.
"If Boris Johnson wins, the Conservatives can say Labour has now lost Scotland [in last year's Holyrood elections] and London and that Labour is on the way out."
Mr Kellner regards the result as a useful indicator of people's mood, albeit a complex one.
He said: "If you go back historically to when we had the Greater London Council and Labour was in Downing Street in the late 1960s and late 1970s, then the Tories won easily.
"Then, when the Tories were in power, Labour won easily in London. I think it's counter-cyclical."
As well as choosing a mayor, voters will elect the 25-member London Assembly. The latter contest has an element of proportional representation.
Mr Kellner said: "As we develop PR systems, voters have learned that they can use their votes differently, not just as protests but to help smaller parties.
"UKIP, for instance, did well in the last European elections and the Greens did well in London.
"Different people will vote for different reasons. In London, all three of the main parties' candidates are high-profile figures, but when a government or opposition is fantastically unpopular, that tends to reveal itself in elections all over the place.
2004 MAYORAL VOTE:
Ken Livingstone (Lab) took 36.8% of first-preference votes
Steve Norris (Con) took 29.1%
Simon Hughes (LD) took 15.3%
2005 GENERAL ELECTION:
Labour - 36.1%
Conservatives - 33.2%
Lib Dems - 22.6%
"In the mid-1990s, when John Major's government was in all sorts of trouble, Tory councillors were losing their seats all over the place.
"In the 1982 local elections, in the middle of the Falklands war, the Tories did extremely well, even though they (local councillors) had no role in the war.
"But it's not that everybody leaps like lemmings according to the national picture. A lot of people regard these secondary elections as a way of sending messages to party leaderships."
London stands out from other UK cities in its size and national and international prominence.
At the last mayoral election, in May 2004, 1.9 million people voted.
This was only about 100,000 fewer than took part in last year's Scottish Parliament election - and about double the number voting in the Welsh Assembly election.
In 2000, Ken Livingstone, after a spat with Labour which saw him leave the party, won as an independent candidate.
Four years later, and back in the Labour fold, he won again.
Of course, Tony Blair went on to take the general elections of 2001 and 2005 comfortably.
But, with the Tories and Labour now vying more closely for the lead in national opinion polls, could London's results be more important than before?
It certainly looks that way, although given that all three main parties have gone for "characters" as candidates the respective party leaders can easily disassociate themselves from a disappointing showing.
Danny Dorling, professor of human geography at Sheffield University, said: "It matters for the rest of the country because local elections - and London is a local election - foreshadow general election trends.
"If Boris Johnson wins, we are probably looking at a Conservative term in office.
"The way London's outer boroughs go is often crucial to national elections. The way they vote is important.
"In about 1992, when the outer boroughs went to Labour, the Guardian headline was 'The incredible shrinking Tories'. It was the beginning of the writing on the wall for John Major.
"But voter interest in London is very low in the north. People see London dominating the national news agenda, with the media forgetting everywhere else
"But it's really interesting, wherever you live. In election terms, London is often ahead of the game."