When a group of immaculately-dressed Sikhs arrived to show their respect on the day I went, a TV reporter fell on them hungrily, as if their presence was especially important. And when the BBC's Newsnight came down to Woolwich a few days earlier, the reporter noted the reluctance of some to speak to the camera for fear of being labelled racists. He asked one woman for her view, who replied that what she felt would never make it on to the air. When pressed, she said that the people who did this should be "sent back where they came from".

A confused response perhaps; one of the two accused was British-born. But what was more interesting was the fact that she had assumed her view would be unacceptable for broadcast. This was a completely understandable reading of the situation on her part. Unlike the more varied and quarrelsome print media, Britain's TV and radio broadcasters stick largely to the prevailing liberal orthodoxies, which in the case of multiculturalism and immigration means a constant emphasis on the celebratory. Its downsides don't interest them, if they even admit (or are aware) that such downsides exist.

In this, they are unquestionably led by the BBC, which sets the news agenda and to an overpowering degree the terms of debate. When one considers that 93 per cent of the UK population consumes some part of the BBC's output every week, and that the corporation accounts for some 70 per cent of news coverage, it is hard to overstate its influence. Of course, we can always watch Sky News or ITN (and, unlike the BBC, we don't have to pay for them either). But the fact remains that the BBC is the public broadcaster, which prides itself (to an almost arrogant degree) on its journalistic standards.

Impartiality is a declared sacred value of BBC News, but on the biggest issues of our day it consistently, almost wantonly, falls badly short. Two new publications highlight the extent of the failings. Ed West's report for the New Culture Forum (of which I am director), Groupthink: Can We Trust the BBC on Immigration? (£10) looks specifically at how that issue has been reported and discussed by the BBC since 1997. Having trawled through hours of broadcasts and transcripts, West proves what many people have sensed for years but have found difficult to put their finger on: that the BBC has given overwhelmingly greater weight to pro-immigration voices even though they represent a minority viewpoint.