The furore over Nick Griffin's appearance on Question Time showed me just how much Britain has changed since I left it in 1992.  As I followed the interminable and intemperate "debate", I felt more and more disconnected. The mob at the BBC Television Centre calling for Griffin and his followers to be burned to death merely added to the feeling. Are those people really my fellow-citizens? They are far scarier than the BNP's pale and baggy losers, yet they belong to a group supported by David Cameron.

"No Platform for Fascists and Racists" was a concept invented in 1970's student politics. I was there, laughing at the Communist dweebs promoting it, but I was wrong. It became National Union of Students policy in the 1990's and, if the outcry against the BBC for giving Griffin a platform is anything to go by, seems perilously close to becoming the norm for "grown up" politics.

The mainstream parties are to blame for the rise of the BNP. They know how many voters feel about current levels of immigration, but they ignore it. They have created a political climate in which merely to seek to discuss it is to be denounced as "racist" and ostracised. Perhaps the fears of the "aborigines", as Griffin charmingly called us, are misplaced. Perhaps our culture will not be lost. Perhaps the social infrastructure of Britain can cope with seventy million souls on our archipelago. But aren't these fears at least legitimate? Are they not worthy of discussion?

The three members of Britain's political cartel frame all national debate within the tight parameters of left-liberal thought. They ignore the declining memberships of their parties that were once genuine mass movements. They turn their back, in some sense, on the very concept of democracy. If some of their snubbed voters and ex-members have turned to the BNP in protest, it's regrettable but hardly surprising. Nor is the way in which they routinely speak of BNP voters likely to win them back.

In 2000, voters tried to break the cosy cartel of Austrian politics by voting for the late Jörg Haider. They put his party into a coalition government and the European Left into a frenzy. A civilised, educated and kindly Austrian friend explained to me at the time "it was the only way to make them listen". The LibLabCon cartel risks the same outcome, unless it engages in real debate and listens to its people. If it had a leader with half Haider's glamour, the BNP would be doing better even now.

Today, the BNP is a statist, authoritarian joke, but so were those student politicians of my youth. Mad ideas can prevail when democracy goes sour.