It was a week from the London mayoral elections and crucial local elections around the country, and Labour had had a bad day. A brewing row over the issue of anti-Semitism had come to a head and resulted in the suspension of both an MP and the former Labour mayor of London.

That evening, the Labour candidate for that same office, Sadiq Khan, stood in bright lights at the center of a sports arena in front of a largely religious crowd of thousands of Jews, Christians and Muslims, to rapturous applause. The Copper Box arena, usually the scene of boxing and fencing matches, was hosting the annual political sport of the Citizens' Assembly. It was to be a night of high emotions and a roaring crowd, playing well to his exuberant style. "Hello London! Shalom, Assalam Aleikum," he bellowed to cheers from the stands.

At a time of heightened tension over the threat of Islamic extremism on mainland Europe, if the polls are right then this London-born Muslim, the son of a Pakistani bus driver who grew up on a housing estate, is poised to lead one of the biggest capitals of the Western world.

For many Londoners, Khan's candidacy is not wholly unsurprising. The capital has become one of the world's most diverse cities. Three hundred languages are spoken and less than half of London's population is ethnically white British. The remainder are a colourful mix of ethnicities from around the world - many of whom were born British in the UK.

That being said the election of an ethnic Pakistani and a Muslim, to one of the most high-profile political offices in Europe would send a powerful message about the city of London and western democracy.

His main opponent in the race is the soft-spoken Conservative MP for Richmond, Zac Goldsmith. Born into a dynastic legacy as the son of the billionaire financier James Goldsmith, his earlier years as an MP were marked by a series of rebellions against the Conservatives that put him at odds with the prime minister.

So where do the two frontrunners stand on London's biggest issues?

Much of the battle for London isn't actually being fought over policy. There is a lot of convergence between the manifestos of most of the candidates, particularly the two frontrunners. They both vow to build more of the houses that London so desperately needs. They both want to work on Crossrail 2, the new expanded rail network into the city. They both are against Heathrow airport expansion and both pledge to tackle London's dangerous air pollution - and the similarities go on.

Tony Travers of the London School of Economics says their policies are so close to each other that the electorate will "find it hard to find a ideological gap between them." Perhaps it is inevitable that the battle lines would have to be drawn over image instead.

'Generation rent'

In the summer of May 2008 London had just elected its first Conservative mayor. Boris Johnson, a flamboyant maverick, won over voters with his charm and his optimism for what was an exciting, dynamic world-class city, recovering from Europe's most deadly terror attacks at the time, in the throes of financial boom before the financial crash that would come to a head later in the year, and the next city to host the Olympic Games.

The London of today feels very different in comparison. The city is younger, yet it is its younger workers whose employment prospects and income fell the fastest during the 2007-2008 crash, and who have enjoyed less of the city's recovery since. Graduates are more likely to be unemployed and living with parents for years before finding work, and, following the rise of tuition fees are likelier to be in high amounts of debt. As for Boris's legacy - 'Generation Rent' might just be it.

London's housing situation is in dire straits and is the city's biggest issue for voters. If all prices rose by the same rate as house rises since the 1970s, a chicken would now cost 51.18 pounds (65.27 euros) - so says Priced Out, a campaign group. The two leading candidates have both pledged to build 50,000 new homes. Boris Johnson pledged the same when he first took office - and not even half that number was built.

Personal feud

Unable to really wage war over each other's manifestos, in recent weeks the campaigns descended into political bickering, with race and religion taking center stage. Khan's professional background as a human rights lawyer saw him defending people he has described as "pretty unsavory." At a recent BBC debate he admitted that he regretted giving the impression that he subscribed to their views. "I've been quite clear I find their views abhorrent." His opponents have argued that there is a link to extremism, calling into question his judgement at a time of increased threat to the city's security. It's a tactic that has been cynically received by many voters.

"At the beginning of this election cycle, I was leaning towards Zac," said Mani from Ilford, despite, as a Pakistani Muslim, sharing the same background as Sadiq Khan. After an opinion piece by Zac Goldsmith the Sunday before elections was burnished with an image of the 7/7 bombings, he got in touch to say he'd changed his mind. "That Daily Mail article was the last straw. Sadiq Khan it is then."

The overall disappointment with both candidates is tangible and many voters face a difficult choice.

"At one point I used to respect both Zac and Sadiq as MPs. They've shown the worst of themselves and highlighted that Westminster is nothing but a circus," said voter Sophia Akram. "Their rivalry has overshadowed what their actual propositions are."

On Thursday, Londoners of all backgrounds will make their choice after what's been described as one of the dirtiest political fights in recent years. Or rather, they will have a say only if they aren't so put off by this battle that they decide not to vote after all.