Former Conservative Party chairwoman Baroness Warsi has resigned from the party in the House of Lords, claiming it has moved to the “far right”.

The peer, who was Britain’s first Muslim cabinet minister during David Cameron’s premiership, accused the party of “hypocrisy and double standards in its treatment of different communities”.

But the Conservatives say she was about to be investigated for allegedly using “divisive language”.

“Baroness Warsi was informed an investigation was about to begin earlier this week,” a party spokesperson said.

“We have a responsibility to ensure that all complaints are investigated without prejudice.”

The BBC has been told the complaints were in relation to a post about Marieha Hussain.

Ms Hussain was found not guilty of a racially aggravated public order offence after holding a placard at a pro-Palestine protest depicting Conservative leader Rishi Sunak and former Home Secretary Suella Braverman as coconuts.

In one post on X, Baroness Warsi congratulated Ms Hussain on her acquittal.

Her resignation comes on the eve of the Conservative Party conference in Birmingham.

Baroness Warsi has previously criticised Tory leadership contenders Robert Jenrick and Kemi Badenoch.

She has also been a vocal critic of the party’s approach to allegations of Islamphobia and language used by Conservative politicians, including Ms Braverman.

She wrote on X: “It is with a heavy heart that I have today informed my whip and decided for now to no longer take the Conservative whip.

“This is a sad day for me. I am a Conservative and remain so but sadly the current party are far removed from the party I joined and served in cabinet.”

She added: “My decision is a reflection of how far right my party has moved and the hypocrisy and double standards in its treatment of different communities.”

Baroness Warsi suggested she would raise some of these issues in her new book, Muslims Don’t Matter.

In a further tweet, she said would “not be gagged on a point of principle” and accused the Conservative Party under Mr Sunak of wanting to “retry and replay” the trial of Ms Hussain.

“It would be unfair to do this whilst continuing to take the Conservatives whip,” she posted.

After the 2010 general election, Baroness Warsi made history by becoming the first Muslim woman in the cabinet as co-chair of the Conservative Party.

A former solicitor with the Crown Prosecution Service, she then served as a minister in David Cameron’s government.

But she quit as the minister for faith and communities in 2014 over the government’s policy on the Israel-Gaza conflict.

She has since criticised the party’s inquiry into Islamophobia inquiry and called it “institutionally xenophobic and racist”.

Resigning the Conservative whip means she will no longer be affiliated with the party in the House of Lords, where she has sat as a peer since 2007.

The party is still choosing its next leader, with the final four candidates set to make speeches at the conference in Birmingham.

An intensive round of hustings and multiple votes will follow the conference from 8 October, lasting three days, until only two candidates are left.

Conservative Party members will then choose which of the final two candidates they want as the new leader, with the result announced on 2 November.