Are you as fed up as I am with what passes for a “debate” over immigration in this country? With the utter falsehoods and lazy generalisations? With the fact-free premises and contorted conclusions?

There are two statements (assumptions?) in particular, repeated incessantly by people on the left and right alike, that make me want to pound my head against a brick wall.

The first is the rather specious claim that critiquing, or even discussing, immigration is some sort of inviolable taboo in modern, multicultural and PC-obsessed Britain. “Just because immigration is deeply controversial,” wrote Labour’s David Blunkett in – where else? – the Daily Mail on 27 October, “that cannot mean that we should avoid talking about it.”

Sorry, but is our former home secretary having a laugh? We talk of little else. Consider the past few weeks: Blunkett’s article was prompted by the Tory Defence Secretary Michael Fallon’s claim on 26 October that migrants from the EU were laying “siege” to the UK and “swamping” British towns. (Fallon himself, incidentally, was only echoing Blunkett’s own use of the word “swamping”, 12 years earlier, to refer to the children of asylum-seekers; while Blunkett, lest we forget, was echoing Margaret Thatcher’s dog whistle, a full 23 years earlier, about the UK being “swamped by an alien culture”.)

The day after Blunkett’s column, the Tory business minister Nick Boles said in a magazine interview that “we can’t control” immigration from the EU. The following day, Ed Miliband and David Cameron clashed in the House of Commons over – yes, you guessed it – immigration and, specifically, the PM’s failure to reduce net migration to “tens of thousands” a year. Then, on 1 November, the Labour MP Ian Austin, a former adviser to Gordon Brown, said his party should “be honest” and “say sorry” for opening the borders to eastern European migrants in 2004.

The second claim that makes me want to tear my hair out relates to racism. Or the supposed lack of racism in this so-called debate. Right-wingers, in fits of faux outrage, denounce the left for crying “racism”. Left-wingers, wrote the Ukip leader, Nigel Farage, in January, call “everyone who wants a proper debate on immigration ‘a racist’”. Lefties, meanwhile, bend over backwards to avoid using the R-word. “It is not prejudiced to worry about immigration,” Miliband declared, after Ukip’s triumph in the European elections in May. “It is understandable.”

Maybe. But to pretend racism doesn’t play a role in generating hostility towards, and anxiety over, immigration is naive, if not disingenuous. Those who piously claim that opposition to immigration in the UK isn’t driven by prejudice, bigotry and hysteria, but rather by “legitimate concerns” over rising migrant numbers and a growing pressure on public services, should try answering the following five questions.

First, why, as Ipsos MORI’s managing director for public affairs, Bobby Duffy, has pointed out, has it “long been recognised in studies of attitudes to immigration that the areas with the lowest immigrant numbers are often those that express the greatest concern about immigration”? And, on a related note, why, in the words of Manchester University’s Robert Ford, an expert on Ukip, does support for Farage’s party tend to be “strongest in areas with relatively low migrant populations”, such as Clacton?

Second, why, when “net migration is down a quarter from its peak under Labour and . . . from outside the European Union is down to its lowest level since 1998” – as Cameron boasted at PMQs on 29 October – has concern about immigration continued to skyrocket, to a point where it now tops the list of voters’ priorities, ahead of the economy and the NHS?

Third, why do people think that far more immigrants live in the UK than actually do? (According to Ipsos MORI, Britons believe immigrants make up 24 per cent of the population. The real figure is 13 per cent.) Fourth, why was 70 per cent of the public telling Gallup as long ago as 1978 that Britain was “being swamped” by people with different cultures, even though net migration at the time was negative – more people were leaving the UK than were arriving – and had been so for more than a decade?

Fifth, perhaps crucially and chillingly, why do a quarter (26 per cent) of Britons – and, tellingly, a majority (51 per cent) of Ukip supporters – think the government “should encourage immigrants and their families to leave Britain (including family members who were born in Britain)”, according to a YouGov poll in April? Isn’t the (voluntary) repatriation of immigrants, including the British-born children of immigrants, a hallmark of good ol’ fashioned far-right, racist politics? A policy advocated only by the BNP?

Yet politicians and pundits continue to hold their tongues. Take Ukip, a political party whose leader publicly worries about Romanians moving in next door and brags about taking “a third” of the BNP’s voters; which allies with a far-right Hitler admirer from Poland in the European Parliament. But don’t call them racist. The truth is, as the former Tory MP Matthew Parris has admitted, that “it need not be racist to talk about immigration but many who do are”. Or as another former Tory MP, the late Eric Forth, once put it, much more bluntly: “There are millions of people in this country who are white, Anglo-Saxon and bigoted and they need to be represented.”

Perhaps. I just wish our two main parties weren’t competing with one another to do so. It’s time to stand up to the bigots, not excuse, indulge or woo them.