Conservative MP Michael Fabricant has been accused of treating the arrest of a Tory colleague on allegations of rape and sexual assault offences as a “laughing matter”.

The long-standing MP tweeted that there would be a “strong turnout” of Tories attending Prime Minister’s Questions on Wednesday to prove they are not the unidentified man told to stay away from Parliament.

“I’ll be there!” Mr Fabricant added, followed by the “winking face with tongue” emoji.

He defended the tweet after a dressing down by the Tory whips and a Cabinet minister criticising the “idiotic” remarks for making “light of a really serious situation”, but subsequently deleted the post.

Scotland Yard has bailed the unnamed MP in his 50s pending further investigation into a string of allegations also including indecent assault, abuse of position of trust and misconduct in public office.

Tory chief whip Chris Heaton-Harris urged the MP to stay away from Parliament but has not suspended the whip, meaning the suspect remains a member of the parliamentary party.

Welsh Secretary Simon Hart criticised Mr Fabricant’s tweet, telling BBC Politics Live: “It’s idiotic, it’s insensitive, and it attempts to make light of a really serious situation.

“I despair when I read stuff like that.”

Deputy Labour leader Angela Rayner said it was “grotesque”, while shadow health secretary Wes Streeting warned “this isn’t a joke”.

“Delete and stop bringing Parliament into (further) disrepute,” Mr Streeting added.

Chris Bryant, who chairs the Commons Standards Committee, responded: “This shows absolutely shameful disregard for the alleged victims.

“You should take this down immediately.”

Fellow Labour MP Charlotte Nichols said: “One of the grimmest things about working in Westminster is not just the regularity with which allegations of rape and sexual assault come up, but the fact people like Fabricant here trivialise these as a laughing matter or quirky bit of gossip complete with (the) emoji.”

The Conservative Party has refused to name the MP facing allegations of sexual offences committed in London between 2002 and 2009.

There are clear legal issues with identifying the suspect, but keeping him anonymous will cast suspicion over other MPs who are not facing any allegations.

Mr Fabricant, who has served as the MP for Lichfield in Staffordshire since 1992, had tweeted: “I am expecting a strong turnout of Conservative MPs at Prime Minister’s Questions today.

“Not only to demonstrate their strong support for #Boris (!!). But also to prove they are not the one told by the Chief Whip to stay at home. I’ll be there! (winking face with tongue emoji).”

According to the Emojipedia website, the symbol used is also known as “crazy face” and “often conveys a sense of fun, excitement, wackiness, buffoonery, or joking”.

The Tory whips spoke to Mr Fabricant about his remarks, with Conservative sources branding them “inappropriate”.

Asked by the PA news agency if he stands by the tweet, Mr Fabricant messaged: “In no way was I making light of rape or any other assault.

“They disgust me.

“I was, however, commenting on the speculation as to who the MP might be.”

But he went on to delete the tweet.

It is not the first time in recent weeks that a Conservative MP has faced criticism for their response to a colleague facing allegations of sexual offences.

Crispin Blunt, who since announced he will stand down at the next election, apologised last month for the “significant upset and concern” caused by his defence of fellow Conservative Imran Ahmad Khan following his conviction for sexually assaulting a teenage boy.