Forty-two votes. Glenda Jackson's winning margin in Hampstead and Kilburn five years ago could hardly have been tighter.
It was England's closest constituency result at the last general election. The third-placed Liberal Democrats were only 841 votes behind, making the seat a genuine three-way marginal.
Ms Jackson is retiring after 23 years in Parliament, and the mainstream parties began their campaigns to replace her two years ago. Conservative Simon Marcus was selected in February 2013, with Labour's Tulip Siddiq chosen six months later. The Liberal Democrats subsequently unveiled anti-extremism campaigner Maajid Nawaz as their candidate.
The constituency covers areas of high Jewish population such as Belsize Park and West Hampstead and includes the JW3 community centre within its borders. Of 78,500 voters, 6.5 per cent are Jewish.
Bookies and pollsters have a clear favourite. Ms Siddiq, a former Camden councillor and ex-Amnesty International worker, is odds on to win. Polling has her around 14 points ahead.
Hampstead and Kilburn
Location: North-west London
Sitting MP: Glenda Jackson (Lab)
Majority: 42
Size of electorate: 78,552
Percentage of Jewish voters: 6.5
Standing in May: Tulip Siddiq (Lab), Simon Marcus (Con), Maajid Nawaz (Lib Dem), Rebecca Johnson (Green), Magnus Nielsen (Ukip)
She is taking nothing for granted. "If the local elections are anything to go by it's now between me and the Tories," she told me in a café next to her Kilburn High Road base.
"The Lib Dems lost every seat they held on the council apart from one. They suffered the sins of what happened nationally. They lost an entire generation of voters because of what happened with tuition fees. I'm not so sure it will be a three-way split this time."
Ms Siddiq said she could have waited for a safer seat, "but I've lived here since I was a teenager, my husband and I live here now and my parents were married here. I couldn't bear to stand somewhere that wasn't my home."
Ms Siddiq, who grew up in Bangladesh - where her grandfather was the country's first president - said suspicions over her relationship with the Jewish community following her selection had dissipated after she reiterated her determination to represent minority groups. She spoke at last December's Limmud conference and at synagogues across the constituency.
On Sunday evening, she appeared with her fellow candidates at a hustings organised by the London Jewish Forum. Alongside the Green Party's Rebecca Johnson and Ukip's Magnus Nielsen, Ms Siddiq, Mr Marcus and Mr Nawaz fielded questions from more than 100 people at Belsize Square Synagogue.
The key issues vexing voters include Labour's proposed mansion tax, which would have a significant impact in areas of Hampstead with some of the highest property prices in Britain.
The controversial policy floated by Labour leader Ed Miliband could do serious damage to Ms Siddiq's chances. She said she had lobbied Labour chiefs to protect pensioners or introduce a London-weighting for the tax.
Mr Marcus told the JC that fears over the possible levy were already aiding his campaign. "The mansion tax is a huge issue. People just don't trust Labour. They don't see Ed Miliband or Ed Balls as people who could run the country," he said. "Most people feel we have done a good job in government."
Mr Nawaz would be one of Parliament's most intriguing characters. A former Islamist who spent four years in an Egyptian jail for his activism as a member of Hizb ut-Tahrir, he is now a leading voice in the fight against radicalism.
His Quilliam Foundation think tank has campaigned against extreme groups, and Mr Nawaz himself was credited with "turning" former English Defence League leader Tommy Robinson in 2013.
A controversy last year over Mr Nawaz's decision to post cartoons featuring Jesus and Mohammed threatened to derail his campaign, with hostile Muslim groups pushing for the Essex-born candidate to be deselected.
At Sunday's event it was clear where his passions lie. His response to a question on tackling jihadis brought thunderous applause not only from the audience, but his rivals as well.
"The two groups of people who have come to symbolise the soft targets of modern-day jihadism have been, unfortunately, those who speak up for free speech, and the Jewish community," he told the shul audience.
"My relationship with the Jewish community around this comes with the fact I, too, am on the front line for speaking out against extremism. It's a precarious role that I have."
Mr Nawaz said his counter-extremism work was winning him support in the constituency, despite voters' primary concerns relating to the economy and healthcare.
"I'm polling about double what the party is doing nationally. The efforts are gaining respect from people. I have a very strong, fighting chance of winning."
Mr Nawaz also spoke of his pride at being the only Muslim speaker at last summer's rally against antisemitism in central London.
Mr Marcus has his own impressive track record when it comes to combatting extremism. In 2010, he ran in the Barking constituency against BNP leader Nick Griffin, finishing second behind Labour's Margaret Hodge and pushing Mr Griffin into third.
That campaign, together with his efforts at a boxing academy he set up for excluded teenagers, was a springboard for him to be appointed to advise a government panel after the London riots of 2011.
Mr Marcus, who celebrated his barmitzvah at the Masorti New London Synagogue in St John's Wood, could become the area's first Jewish MP for more than 20 years.
He dismissed the current polling as "nonsense. Tulip, just like Maajid, is a good candidate. But everyone knows which way the wind is blowing - you cannot underestimate the economic issues. Our door-to-door work shows people are switching to us."
It was noticeable that at the Jewish hustings there was not one mention of Israel in two hours of audience questions. But Mr Marcus later said he was aware of Jewish voters who felt "incredibly let down on Israel by Labour". Ms Siddiq said the issue had not come up on the doorstep.
