Glenda Jackson: How to beat the fascists? Build houses ...

There have been few more sickening sights in politics than the spectacle of Nick Griffin celebrating his election to the European Parliament.

But it's important we don't let our disgust overcome our reason. Last night wasn't the triumph Griffin and his acolytes had been hoping for. At the start of the European election campaign he had confidently boasted he would secure a minimum of seven seats. As the expenses scandal broke, he raised his prediction to 12. Even as late as yesterday morning, Griffin was estimating four gains, including one for his organ grinder Simon Darby, the man who described Archbishop Sentamu as a "spear thrower".

Make no mistake, one BNP member is shaming. Two is a moral catastrophe. But this is not the "breakthrough" that Griffin craved and many of us feared. The number of people voting for his unique cocktail of racism and hate actually fell compared to five years ago. The BNP share of the vote rose a paltry 1.3 points. And all this against the background of recession, expenses and ministerial resignations. At least the way ahead is clear. The days of arguing whether we should confront or ignore the BNP are over. We won't confront them. We will tear into them. We will highlight and expose and destroy their agenda of prejudice and bigotry and division.

We also have to realise that our political parties, however principled, cannot lead the fightback against extremists who take pride in positioning themselves beyond the political mainstream. The anti-fascist campaign group Searchlight, based in my constituency, constructed a unique coalition of faith groups, trade unionists, business people, celebrities and voluntary organisations to face down Griffin's storm troopers. They ultimately failed to prevent his election but without their campaign the nightmare of a dozen BNP victories could have become reality. Those who yearn for a "new progressive consensus" would do well to follow Searchlight's lead.

But while politicians cannot take the lead, nor can we abrogate our responsibilities. We must be tough on fascism, and tough on the causes of fascism. A social housing revolution; a renewed and sustained regional investment strategy; policy priorities that reach out to voters who have never stepped inside a focus group. These are the weapons that Nick Griffin fears most. Anything that undermines social, political and yes, racial, inequality undermines, fatally, his platform of extremism.

Within a year, we face our defining reckoning with the British National Party. Griffin believes the ultimate prize, a parliamentary seat, lays within his grasp. We have less than 12 months to prepare ourselves. That will be the moment that determines whether last night was after all, the BNP breakthrough, or whether it was the moment when the enemies of extremism drew a line in the sand. Nick Griffin should beware – after last night he crosses that line at his peril.

Glenda Jackson is Labour MP for Hampstead and Highgate