A group of Conservative councillors has been suspended as a former Tory chair condemned the latest “vile evidence of racism within the party at every level”.

A dossier sent to party headquarters contains alleged Islamophobic and racist social media posts made by current and former Tory officials, who shared material on Facebook and Twitter.

Among the inflammatory comments was one posted in 2017 by a Walsall councillor in which she agreed with a post suggesting all aid to Africa to help starving people should be ended.

She replied: “I totally agree with you. It’s nature’s way of depopulation.”

In a Facebook post in 2016, a Bournemouth, Christchurch and Poole councillor said: “I hate to ban anything really but I’d suggest we start with mosques!”

The same councillor responded to a link to an article about calls for an inquiry into Islamophobia in the Conservative Party by saying: “How about them calling for an inquiry into Islamist rape gangs grooming underage, underprivileged white girls?”

And a parish councillor in Sandiacre, near Nottingham, referred to Muslims as “the enemy within” in a 2018 Twitter post, claiming “spineless governments [sold] us to slavery of the Muslims”.

Baroness Warsi, a party chair under David Cameron, said her party – under three chairs and two prime ministers – had failed to act on Islamophobia.

“Here we are, four years later, with dossier after dossier, dozens and dozens of cases, with the most vile evidence of racism within the party at every level – from members of parliament all the way down to our ordinary activists – the latest being these 25 former and current councillors,” she warned.

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“I am starting to question how much needs to come to light before the party finally acknowledges we have a serious and deep problem.”

In the light of the allegations, a Conservative Party spokesperson said: “All those found to be party members have been suspended immediately, pending investigation.”

But Baroness Warsi said “similar” promises had been made before, adding: “Then it has come to light that people have been suspended for less than a week – and when media attention moves on they are let back in to the party.”

The dossier was compiled by anonymous Twitter user @MatesJacob, whose bio describes them as “investigating institutional racism and Islamophobia in the Conservative Party”.

Referring to London’s Muslim mayor Sadiq Khan, one Kettering councillor posted on Facebook in 2018: “That this vile creature was a [sic] elected Mayor of London tells me all I need to know about that anti British city.”

And a councillor in Redcar and Cleveland, shared an article on Facebook in 2017 which claimed Muslims in Germany were calling for an end to Oktoberfest because it was “un-Islamic”.

He then “liked” comments beneath his post, including one which said: “They can go back to where they came from. Try going to a Muslim country and ask them to stop Muslim traditions because it offends incoming Christians How outrageous is sharia behaviour [sic].”

Another post he “liked” said: “If you don’t like it get the f*** out and go home.”

The Conservative spokesperson added: “The swift action we take on not just anti-Muslim discrimination, but discrimination of any kind is testament to the seriousness with which we take such issues.

“The Conservative Party will never stand by when it comes to prejudice and discrimination of any kind.”