The Conservatives managed sweeping victories in the London elections in 2006 and the majority of national polls show them with a healthy lead. In theory they should be headed for a victory in the London mayoral election. However, the couple of polls we’ve seen so far have shown Ken Livingstone and Boris Johnson neck and neck, with the mayor’s lead as low as one per cent.

The mayoral election won’t be a normal contest fought on strict party lines. Both candidates are larger than life characters, members of that tiny group of politicians easily identifiable to even non-anoraks by just their first name. A voting intention poll back in November revealed both Tories for Ken and socialists backing Boris.

Livingstone’s support is no doubt boosted by being seen to have done a good job. In sharp contrast to a Labour government that has dire approval ratings, a majority of Londoners think Ken is actually doing rather well. After seven years in the job, the annual Ipsos Mori poll for the Greater London Authority found 51 per cent thought he had done a good job, with only 23 per cent dissatisfied. Those who approved of Ken’s performance most commonly cited the congestion charge and transport improvements as the reason.

His main opponent is no normal Tory candidate either. Johnson has popularity and profile well beyond his party political role. In 2007 YouGov used to run weekly polls tracking the popularity of high-profile politicians and invariably Boris would come near the top. He was easily the most popular politician among young people.

Normally people become more Conservative as they get older: in any normal poll you find Labour and the Liberal Democrats dominating among young people and pensioners being strongly Conservative. In the last full-size mayoral poll, carried out by YouGov in December, Boris led among over-55s and Ken among the middle age ranges, but under-24s supported Boris over Ken by 51 per cent to 33 per cent.

This is probably both a blessing and a curse for Boris. He can reach out to young people who don’t have an interest in politics and will no doubt be able to inspire armies of young t-shirted volunteers to campaign for him come May. However, polls so far have not taken into account how likely people are to vote, and under-24s are the group with the lowest actual turnout at elections.

Boris also seems more popular among men than women. It may be his blokeish appearances on Have I Got News For You that appeal to men, or perhaps women are more reluctant to support a politician who cheated on his wife and allegedly procured an abortion for his mistress.

While Boris seems to have remained popular despite his gaffes, Ken faces his own problems. So far we don’t know if the attacks on the mayor and his advisor Lee Jasper in the Evening Standard and Channel 4’s Dispatches have really damaged him. The only poll carried out since the programme, and initially seized upon as evidence that Ken had emerged unscathed, turned out to have a sample size far too low to put any confidence in at all. The Evening Standard’s attacks may yet turn out to have drawn blood.

In such a close race it is likely to come down to second preferences. The Liberal Democrat candidate, Brian Paddick, has so far failed to make any impact, languishing in single figures. It will probably be the second preferences of people who vote for him that decide the election. The polls show Brian Paddick’s supporters will split in favour of Ken. Collectively though there are as many ‘Other’ supporters – Green, UKIP, Respect and BNP voters – as there are Paddick supporters and collectively their second preferences split in favour of Boris. On the polls alone this election is too close to call.