Downing Street intervened in the Conservative party’s handling of allegations of anti-Muslim comments, issuing a private apology after two Tory officials resigned in protest at their complaints being ignored for several months, leaked emails obtained by BuzzFeed News reveal.

Two Conservative association chairs, Ajay Jagota and Gerard Leake, accused party chair Brandon Lewis and the CCHQ complaints department of failing to take action against a Tory councillor who is alleged to have made an anti-Muslim remark.

In revelations that cast fresh doubt on Lewis’ claim to have a “zero tolerance” policy on anti-Muslim behaviour, the leaked emails show he was first made aware of the allegation in September 2018 but neither he nor the party’s complaints unit responded despite repeated requests for answers.

When Theresa May was informed in January this year that the two association chairs had resigned saying their complaints had been ignored, she asked her senior adviser David Beckingham to respond. In his letter to Jagota, he apologised and said he had obtained assurances from CCHQ the complaint was being investigated, the leaked correspondence shows.

“I was sorry to read of your concerns, and that you had not received a response regarding your complaint,” Beckingham wrote in the latter dated Feb. 15. “I have spoken to Conservative Campaign Headquarters who have assured me that your complaint is being investigated and that you will receive an update shortly.”

“I am sorry again to hear your concerns and I hope that this matter can be resolved satisfactorily,” he added.