Hate crimes against Muslims in the UK spiked in the weeks after Boris Johnson's controversial Telegraph column last year comparing women who wear the burqa to "letterboxes" and "bank robbers."

Incidents recorded by the anti-racism group Tell Mama, suggest 42% of street attacks in the following weeks referenced Johnson or his words.

Johnson has repeatedly refused to apologise for the comments.

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There was a spike in hate crimes against Muslims in the UK in the weeks after Boris Johnson compared women who wear the burqa to "letterboxes" and "bankrobbers," according to statistics compiled by an anti-racism group.

UK prime minister Boris Johnson last year was the subject of an internal Conservative party investigation after he made the comments in his then Telegraph column.

Johnson ultimately faced no action by the party. However, the anti-racism group Tell Mama, which records reports of hate crimes against Muslims, say there was a spike in incidents following the row.

Anti-Muslim incidents increased by 375% from 8 incidents the preceding week in August 2018, to 38 in the week after, the group reports, adding that in the following weeks 42% of reported street attacks directly referenced Johnson or the language he used.

Read more: Boris Johnson wrote that 'Islam is the problem' and defended Islamophobia as a 'natural reaction'

Read more: The Islamophobia scandal in the Conservative party goes 'right up to the top'

The group also reports that "of the 38 anti-Muslim hate incidents in the first week following Mr Johnson's comments, 22 were directed at visibly Muslim women who wore the face veil."

Johnson has a history of making controversial comments about Muslims and Islam.

In 2005, Johnson wrote in the Spectator that he believed it was only "natural" for the public to be scared of Islam.

"To any non-Muslim reader of the Koran, Islamophobia — fear of Islam — seems a natural reaction, and, indeed, exactly what that text is intended to provoke," he wrote.

"Judged purely on its scripture — to say nothing of what is preached in the mosques — it is the most viciously sectarian of all religions in its heartlessness towards unbelievers."

In the wake of the London bombings, he also questioned the loyalty of British Muslims and insisted that the country must accept that "Islam is the problem."

"It will take a huge effort of courage and skill to win round the many thousands of British Muslims who are in a similar state of alienation, and to make them see that their faith must be compatible with British values and with loyalty to Britain," he wrote.

"That means disposing of the first taboo, and accepting that the problem is Islam. Islam is the problem."

He added: "What is going on in these mosques and madrasas? When is someone going to get 18th century on Islam's medieval ass?"

Former Conservative co-chair Baroness Warsi told Business Insider last year that Islamophobia goes "right up to the top" of the Conservative party.

"It's very widespread [in the Conservative party]. It exists right from the grassroots, all the way up to the top," she told BI.

She added that Islamophobia was being deliberately ignored at the highest levels for electoral reasons.