Boris Johnson, a man who until recently represented the United Kingdom on the world stage as foreign secretary, has compared women wearing niqabs to “letter boxes”and “bank robbers” in a national newspaper.

Writing about his opposition to Denmark’s burqa ban in the Telegraph, the senior Tory has really shown off his qualifications for high-level diplomacy by ridiculing Muslim women across the world who wear the burqa or niqab.

The Muslim Council of Britain issued a statement accusing him of “denigrating” women and “pandering to the far right”.

Chair of the Conservative Muslim Forum Mohammed Amin told BuzzFeed that Johnson should apologise, and warned his comments “will be seized upon by others from the far right”.

The Tory peer and former party chair who served as the first Muslim woman in cabinet in 2010-14, Sayeeda Warsi, tweeted that Johnson was using “dog whistle” language about Islam – referring to his remarks as “business as usual” in the Conservative party, which she says is “in denial on Islamophobia”.

Theresa May refused to condemn her former minister’s language.

Johnson’s piece comes soon after reports that he has been regularly in contact with Steve Bannon – the former Donald Trump strategist exporting his clash of civilisations extremism to Europe – who has also met other influential Tory politicians like leading backbench Brexiteer Jacob Rees-Mogg and cabinet minister Michael Gove.

From former London mayoral candidate Zac Goldsmith’s racially-charged campaign strategy to pick up non-Muslim Asian voters in 2016 to senior Tories flirting with leading figures and inflammatory language of the far right, the party is clearly not shy about being perceived as Islamophobic.

The prejudice isn’t a new one among Tories. Having run as a Tory candidate in Leigh in 2010, Shazia Awan (who has since left the party) revealed in the New Statesman the prejudice she experienced as an Asian Muslim woman.

“There is no place for ethnic minorities in the Conservative party,” she wrote of her journey since joining the party in 2007. “I felt I was nothing more than a tick-box exercise for them: a young, articulate Asian, Muslim woman.”

In 2011, Warsi made headlines by saying Islamophobia had “passed the dinner table test” in a speech to Leicester University as Conservative party chair. Last year, she told me this statement – which caused outrage at the time – is now “bland”, so socially acceptable has Islamophobia become.

Indeed, Islamophobic hate crimes had increased fivefold last June in the aftermath of the London Bridge attacks, when there was also a terrorist attack on Finsbury Park mosque in north London.

In line with anti-Muslim sentiment across the country, Warsi told me that her party was “writing off British Muslims” and said its “divide-and-rule behaviour of the colonial past has got to stop”.

She also revealed that she’d sent an advanced copy of her book on Muslim Britain, The Enemy Within – which outlines the shortcomings and dangers of government policy towards Muslim communities – to Theresa May, the then Home Secretary Amber Rudd and other ministers.

They don’t seem to have read it, because since then the Muslim Council of Britain has officially called for an inquiry into Tory Islamophobia, citing a pattern of over ten Islamophobic occurrences from Tory candidates or representatives from this year alone.

In March, the Tory MP Bob Blackman shared an Islamophobic post on his Facebook page, entitled “Muslim Somali sex gang say raping white British children ‘part of their culture’ ” (he later took it down, calling it an “error”).

Soon after, he was found by Vice to be a member of far right and Islamophobic Facebook groups (which he removed himself from, saying he was “completely unaware” of their content).

No action was taken by the party against him – even though the MP has past form.

Tory councillors and council candidates have also recently been caught propagating similar far right and Islamophobic content (for example, in April, Calderdale councillor Mike Payne was suspended after sharing an article which referred to Muslims as parasites).

Warsi has backed calls for an inquiry, accusing her party of pursuing an age-old “fuck the Muslims” strategy of ignoring – or denying – Islamophobic prejudice in their ranks.

This idea that it’s partly a political calculation to allow Islamophobia to flourish is detailed in Warsi’s book. She gives her impression from the top tiers of the party that – because a Conservative government doesn’t rely on Muslim voters – they don’t bother fighting the prejudice, and are happy to fan the flames of division.

“Unfortunately politics determines who you think is worth fighting for, and who you think it’s OK to vilify and get away with it,” she told me.

This has been pinned on the Tories’ election guru Lynton Crosby, who reportedly said Johnson’s London mayoral re-election campaign in 2012 shouldn’t focus on winning votes from the “fucking Muslims”.

One Tory MP has described Islamophobia in campaigns to me as a “cold, Lynton Crosby calculation of the dog whistle variety”.

And this divide-and-rule campaigning hasn’t stopped – only five months ago in the most recent elections, a Romford Conservatives campaign leaflet distributed in Havering was accused even by Tory figures of “racist signalling” (it referred to “Mayor Khan” and warned of the borough “resembling” neighbouring “inner-city” areas and “our cherished union jack flag being taken down”).

I’ve written before about how liberal Tories have been shamefully silent on this strategy. It’s this silence that allows prejudice – fuelled by political calculation – to reach, as Warsi puts it, “all the way up to the top” of the Conservative party.