I tell the MP that she looks fine — she does — she’s 37 and without the slap looks ten years younger. But she borrows some mascara and sets off for the toilet, anyway. She returns hair down and frizzed, pink lipstick applied and jacket soberly straightened. At the bottom of the smart grey trouser suit, she’s wearing a pair of funky trainers with glittery stripes.

I tell her that on my way to her offices in the East London constituency of Bethnal Green and Bow, I passed two women wearing the head-to-toe Muslim burka. You see quite a few burkas in the second-most Islamic constituency in the country, with an electorate that is almost 50 per cent (largely Bangladeshi) Muslim.

King is a noted feminist and PPS to Patricia Hewitt, the Trade and Industry Secretary and Minister for Women. She recoils strongly from the oft-appended tag “Blair babe”. So how does she feel about the burka-clad women who walk the streets three paces behind their men? “Well, my views have changed,” she replies. “Like a lot of people, I used to be confused by it . . . I assumed it was something being imposed on them.”

She shifts in her seat slightly. “Of course, it is imposed to an extent, the same way as Western women wear make-up. But just because I wear make-up, it doesn’t necessarily mean that I am being manipulated by some greater patriarchal force. But, honestly, I’ve got to know those women now — and it’s often the ones wearing burkas who’ll give you the biggest mouthful of all.”

Really? I’m amazed. “No, absolutely. The scales sort of fell from my eyes. I’d defend the right of any of my constituents to wear one . . . obviously not in schools, because teachers have to see kids’ faces, but if they’re over 18 and not in school, certainly. It’s their choice.”

Over the past few years, it has often seemed as though King’s job has been all about reconciling apparently irreconcilable views. When she supported Tony Blair and voted for war in Iraq, her grip on an otherwise solid Labour seat began to look shaky. The following spring, 2003, anti-war posters sprouted in this part of London. It didn’t matter that King’s stance on Iraq was at least consistent (having founded the All Party Group on Genocide Prevention in 1998, she first started calling on the UK Government to “do anything and everything in its power” to get rid of the genocidal Saddam Hussein a year later), her decision to back hostilities led to some pretty savage local vilification. She says: “People didn’t tend to accept my view as being genuinely held from all those years ago. They thought I was toeing the party line, voting for the war for the sake of my job, which is ironic because there’s nothing more guaranteed to lose me my job than supporting the war.”

The vultures began to circle. Late last year George Galloway, standing for the anti-Blair, anti-war party Respect, announced his intention to run against King in the general election on May 5. The scrap has become serious: the King camp had to apologise and pay money out of court for a press release that falsely accused Galloway of sexual harassment. Yet it has also guaranteed her maximum support from Labour’s campaign HQ. “I can’t imagine anyone would be very thrilled to have him [back in Parliament] again,” she says.

Has she seen much of Galloway so far? “Enough of him,” she mutters. It turns out he’s been in Bangladesh. She adds: “He’s already on the front page of Bangladeshi newspapers being sold here in Tower Hamlets because of what he’s doing there. And, yes, that has an effect.”

What worries her most, however, is not that Galloway will win the seat outright, but that Respect will split the vote to let in the usually second- placed Tories. The loss of this poor, staunchly working-class part of London would be an embarrassment for Labour — but it’s not impossible. Gordon Brown visited the constituency to support King last week.

In some quarters, with shocking predictability, the fact that King is Jewish has also proved “hugely problematic”. She’s fairly thick-skinned about this, however, and takes great pride in her fascinatingly mixed roots: dad a political activist African-American (who fled a racist conviction for draft-dodging in Georgia and whose brother was lawyer to Martin Luther King); Jewish mum with Hungarian lineage on one side and poor Scots-Irish on the other (a teacher, whose sister is Miriam Stoppard). “There’s a bit of Native American Indian in there somewhere, too,” she says, “and probably some white slave-master.

“I have lots and lots of people saying they won’t vote for me because I’m Jewish. And it is very shocking, but it’s also hilarious in some sense. Growing up (in North London), it was the black side of me that always attracted racist comment because that was the visible bit. Though at school, because the kids knew my mother was Jewish, I did get called ‘yid nigger’ sometimes. But now, well, being black is really cool in Britain. Being Jewish? Oh no! I’m always losing out on one side or the other.”

Her credentials are impeccably pro-Palestinian, however. “I’m anti-Ariel Sharon and anti-ethnic cleansing. The fact is . . . the Palestinians are offering to settle for 22 per cent of historical Palestine and I really think it’s incumbent upon the Israeli Government to make that possible.”