Joan Smith: It's not a black and white issue, but my vote's for Trevor, not Ken

Livingstone parks his values when they're inconvenient

Lord Baden-Powell, founder of the Scouts, had a theory about young men going through a period he called the "rutting season". He meant this in relation to sex, but I find the image of males locking horns with other males coming to mind with increasing frequency in relation to the Mayor of London. Though he is no longer in the first flush of youth, shall we say, Ken Livingstone is about as open to civilised debate as a rutting stag; last year, a Jewish reporter from the Evening Standard who annoyed him found himself compared to a concentration camp guard. Then it was the turn of the Reuben brothers, a pair of Jewish property developers who were told by Livingstone to "go back to Iran and try their luck with the ayatollahs".

Now, with much stamping, crashing and breaking of branches, Livingstone has burst from the undergrowth to savage Trevor Phillips, chair of the Commission for Racial Equality. Phillips's offence? He has questioned the meaning of multiculturalism, challenging the notion that the Notting Hill Carnival is a triumph of this much-discussed phenomenon. Speaking on BBC radio last week, Livingstone claimed Phillips has become so right wing "that I expect soon he'll be joining the BNP".

Actually, Phillips's point was that the carnival is a one-off, a great party that doesn't represent the everyday culture of most of London's communities. This seems to me uncontroversial, as well as raising an important question: what is multiculturalism? These days, everyone is so busy taking positions - right-wing columnists blame it for everything from mass immigration to terrorism, while the hard left denounces anyone who questions it as racist or fascist - that it's hard to know what the word means. Phillips's pronouncements on the subject are robust - earlier this year he suggested that Muslims who want to live under Islamic law (sharia) should leave the country - but more coherent than anything the Mayor of London has come up with.

Livingstone's take on multiculturalism certainly isn't mine. It's a form of relativism that allows him to park his values when they're inconvenient and embrace religious extremists with repellent views on women and homosexuals. Living in a society that has abolished the death penalty, Livingstone welcomes to London a Muslim cleric whose website discusses whether death is the appropriate penalty for gay men, and appears at public events with an academic who refuses to call for a ban on the hideous practice of lapidation.

Of course, multiculturalism is about respecting difference, but it isn't about recognising no boundaries. I am very happy to live in a heterogenous society where we don't all have the same skin colour, wear the same clothes, eat the same food, follow the same religion or vote for the same political party. Underlying all that, however, there has to be a common set of values, which we recognise through respect for the rule of law. Most Roman Catholics, for instance, oppose abortion but accept that it's legal in the UK and, unlike in the US, they do not attack doctors who perform terminations or blow up abortion clinics.

In fact, the biggest threat to multiculturalism comes not from organisations such as the BNP but politicians such as Livingstone who refuse to have this debate, seeking to close it down with accusations of racism and Islamophobia. The UK is a diverse society, but it won't remain so if millions of ordinary people feel they're not allowed to criticise the minority who hate gay people, treat women as second-class citizens and support political or religious violence.