All the political parties have lined up to attack Nigel Farage over his interview on Channel 4 News on the evening of the Charlie Hebdo terrorist murders.

Tessa Jowell led the excited, baying Westminster-village pack by describing his remarks about multiculturalism as ‘sickening’. Tory communities minister Eric Pickles also joined in, as did Nick Clegg and legions more.

And the Daily Mail chose to emphasise in its report the word ’sickening’, suggested that they (perhaps for the first time ever?) were at one with Ms Jowell .

His crime? Jon Snow – as the transcript of the four-minute interview shows – was determined to put it Mr Farage that the slaughter meant that his case for withdrawing from the EU was now literally shot. Instead what was needed was ‘European unity”.

What a bizarre proposition – Snow was effectively suggesting that in order to deal with terrorism, a Federal Republic of Europe needs to be created overnight.

Unsurprisingly, Mr Farage was having none of it. He put the alternative view that good neighbours need fences, and indeed that those fences were the key to keeping relationships sweet and properly boundaried.

In his argument, he also pointed out that a consequence of multiculturalism was that, regrettably, some of the separate cultures ( it was obvious here he meant Islam) were shielding a tiny minority who were capable of perpetrating such acts of terror.

Blunt? Yes. Of course. But sickening? And political point-scoring?

The whole problem with the Westminster village – as Roger Scruton lucidly points out in his new book “How to Be a Conservative” in his section on the disgraceful mob-rule treatment of the Bradford teacher Ray Honeyford – is that their approach to immigration and multiculturalism has led to a shutting down of genuine debate about how our society should develop in the wake of by far the biggest influx of immigrants in British history.

Such debate doesn’t imply the adoption of beliefs that that all terrorists are Muslims or that Islam per se breeds terrorism. I obviously can’t speak for Farage, but I don’t believe for a second that is what he was saying.

What is required is an honest appraisal of what is going on after and because of, the massive ‘multicultural’ experiment to which New Labour subjected us to without a scrap of consultation.

Nigel Farage and his party may be wholly wrong or misguided in singling out multiculturalism as a causative factor in terrorist attacks. Their words might be inflammatory in some quarters, especially the excitable Ms Jowell. But it is a debate we need to have. And turning on Farage and his party as if he and they are nasty racists for mentioning it is itself a sign of bigoted intolerance.

The reality is that as we enter the long and tedious home straight towards the 2015 general election, immigration is so high on the political agenda – and Ukip has two by-election victories under its belt – because the Westminster class has for more than a decade refused to contemplate properly the consequences of both the multicultural experiment and virtually uncontrolled immigrant flows.

In the Snow interview, Farage was reacting partly to the Charlie Hebdo massacre and partly to the news that yet again, with wearying predictability, David Cameron – after his meeting with Angela Merkel – had accepted that the free movement of people directive cannot be diluted or countermanded.

This shows that the reality is that most of the Westminster class is still refusing to take on board true concerns about immigration. Like him or loathe him, Farage is a messenger of a large section of British public opinion on this topic.

The Jon Snow interview – in both its framing and the fall-out baying – illustrates vividly that the only reaction our political class have to this strand of opinion is to turn on the messenger. They don’t want debate – they want to shout him, his party (and the public) down by name-calling. It is they, not he, who are using the horror of Paris to score points. Shame on them.