Senior MP Julian Knight has said he is facing a “witch hunt” after his demand for a return of the Tory whip – after a police probe into him was dropped – was rejected over “further complaints”.

Mr Knight, who was suspended from the Conservative Party after a serious sexual assault allegation was made against him, had called for his “immediate return” to the parliamentary party after the Metropolitan Police confirmed it was no longer investigating the matter.

But Chief Whip Simon Hart rejected that demand over “further complaints made to the Whips’ Office”.

The decision prompted an extraordinary attack by Mr Knight on his former party colleagues, as he accused the Whips Office of pursuing a “witch hunt” against him in a bid to stop him “naming names”.

The MP, who has represented Solihull since 2015 and is chairman of the Commons Digital, Culture, Media and Sport Committee, had strongly criticised the Whips Office and the Met in a statement following the police decision to drop the investigation into the “single, false and malicious allegation”.

“In publicly naming me in connection with the allegation, the Conservative Whips’ Office acted disgracefully and in breach of natural justice by removing my anonymity. Their actions meant my name was dragged through the mud and my good reputation immeasurably damaged,” he said.

“The conduct of one person in the Whips’ Office, and the language used towards me, was particularly egregious.”

Mr Knight also pledged to use “every legal route available to pursue those inside and outside Parliament” involved in the allegation.

The Whips Office moved quickly to confirm that Mr Knight would not be rejoining the party, despite the Met decision.

A spokeswoman for Mr Hart said: “Following further complaints made to the Whips’ Office, we will not be restoring the whip to Julian Knight.

“These complaints, if appropriate, will be referred to the relevant police force, or appropriate bodies.”

The Whips Office has not released details about what the “further complaints” relate to, but it means that Mr Knight – who had recused himself from Parliament until the case was resolved – will remain as an independent MP.

He condemned the response of the Whips Office, accusing Mr Hart of engaging in a “desperate attempt to cover up the identities and motives of those in Parliament who colluded for many months to bring the false allegation against me to the police”.

“The police have confirmed today that there is no evidence to support that allegation and closed their investigation. They did not even need to interview me to do so,” he said.

“Yet the Whips Office now seems intent on continuing a witch hunt against me in an attempt to prevent my naming names.”

A spokeswoman for the Whips’ Office declined to comment on Mr Knight’s response.