I'm not at all Jewish, in general. In fact I'd go so far as to say that I've never been Jewish at all.

Now, before my mother keels over, let me explain that I'm not talking about birth, religious practice, culture or all the many other ways in which I am as kosher as the average Jew, assuming such a thing exists. I'm only non-Jewish when it comes to making political choices. More than 30 years since I got the vote, my Jewishness has never affected how I use it.

Everyone I've ever considered voting for has been sensibly reasonable on matters to do with racism, sexism and even Zionism. I'm a Jewish woman, of the soft left persuasion, and so is my MP, but even these similarities did not (and probably will never) persuade me to vote for her.

Some Jews are not like me. There are some who put Israel at the centre of their political life, and decide which party or candidate to vote for on the basis of Middle East policy. "Is it good for the Jews?" is their constant test. I am sure there are also Jewish voters who would vote for one of "unzerer" whatever their political stance.

But that is not the case for me, and it's why I resent the whole notion of a Jewish vote. If I wanted Israel to be central to my politics, then I would make aliyah. I vote on the basis of what is good for Britain and I try to think beyond my own narrow interests.

If Israel were central to my politics, I would make aliyah

Obviously, I couldn't bring myself to even consider backing the BNP but I would feel like that whatever my ethnicity or religion. My commitment to social justice and fairness, which makes me lean leftward, is rooted in Judaism - but I know and respect Jews who apply similar values to justify backing the Tories.

We Brits are not like American Jews, who are more comfortable with notions of a Jewish vote and are wooed en masse by politicians offering assurances on Israel. Only this week , Barack Obama went to the US Holocaust Memorial Museum in Washington to announce new technological sanctions against Iran and Syria, speaking to a crowd of influential Jewish leaders.

In the UK, we are too small in numbers to act as a bloc, and we wouldn't listen to our community leaders even if they dared to tell us how to vote.

However - and I'm sure you saw that coming - this year my views have changed. For the first time, I intend to cast a 100 per cent Jewish vote.

Ken Livingstone is the obvious reason for my change of heart, and how I resent the knuckleheads at the Labour Party who picked him as their candidate for London mayor. Ken's disdain for Jewish sensibilities has been obvious for years, showing itself in the casual way in which he tosses insults and picks his friends. He has shown himself to be, at best, stupid and rash. He is not someone I would want running my city. But the other choices on offer offend me as an intelligent voter.

Do I want blundering Boris, whose main appeal seems to be his elusive blond charm? Or Brian Paddick, last seen munching kangaroo testicles in the jungle My first preference vote will be a protest against them all, and will go to independent candidate Siobhan Benita. But my second preference will be cast to keep Ken out, and the reason - oh horrors - is that Ken's bad for the Jews.

I suspect that this will not be the last time that I identify as a Jewish voter. The French presidential election has been marred by Nicolas Sarkozy's attempt to woo right-wing voters by calling for restrictions on halal and kosher meat, a subject enthusiastically taken up by the French prime minister.

Intolerant secularism is growing fast in popularity in continental Europe, and more slowly here. I suspect that both kashrut and circumcision will become political issues in the UK, and Jewish voters may be forced to consider if they are prepared to vote for someone with no understanding or respect for their religious traditions.

When mainstream politicians shmooze blocs of voters - whether "secular" or "Muslim" - minorities and individuals get squeezed, insulted and ignored. Let's hope for politicians who work to unite people, not set them against each other, so I can go back to being not at all Jewish again.

Keren David's latest novel is 'Lia's Guide to Winning the Lottery' (Frances Lincoln)