Sir Lindsay Hoyle has condemned threats made against MPs after they approved a new process to enable colleagues arrested for serious offences to be banned from attending Parliament.

The Commons Speaker said it was “wholly unacceptable” for people to try to “intimidate or threaten” any MP, labelling it an “affront to our democracy”.

MPs voted by a majority of one in favour of amending the risk-based exclusion policy to ensure it is triggered when an MP is arrested on suspicion of committing a violent or sexual offence, rather than at the point of charge.

The initial House of Commons motion tabled last year had stated a risk assessment would take place on whether an MP should be prevented from attending the parliamentary estate if they were arrested for such an offence.

In March, the motion was revised so a ban was possible only at the point of charge. But MPs this week voted 170 to 169 in favour of reverting to the threshold being an arrest.

The amended motion was then passed without the need for a formal vote.

Making a statement to the Commons on Thursday, Sir Lindsay said: “On Monday night the House agreed a new policy based on a report by the House of Commons Commission setting out the steps to be taken if a member is arrested on suspicion of committing a violent or sexual offence.

“This involves a risk assessment carried out by a panel, which may recommend that a member may be excluded from the parliamentary estate.”

He added: “As the House knows, the main motion as amended was agreed to without division. No member voted against the exclusion policy.

“I understand that some honourable members have received threats on social media since the vote on Monday.

“Let me quite clear: any attempt to intimidate or threaten any member of this House is wholly unacceptable, it is an affront to our democracy and to the constituents who elected us, and contempt of this House.

“Any member who receives threatening communications should report them to the parliamentary security directorate or, if appropriate, to the police through the parliamentary liaison investigation team, who will be able to investigate further.”

Sir Lindsay has written to MPs to remind them of the support services available, adding: “We take this very, very seriously.”

Labour party annual conference 2015
Shadow Commons leader Lucy Powell spoke at business questions on the Commons (Jonathan Brady/PA)

Speaking at business questions, shadow Commons leader Lucy Powell said of the risk-based exclusion policy: “Since Monday I’ve been struck by how many women in less privileged and powerful positions than mine have approached me to say thank you and how this decision has changed how they feel about working here.”

Ms Powell went on to highlight the launch of a guide to tackle conspiracy theories, asking Commons Leader Penny Mordaunt: “Is she as disappointed as me then to see (health minister Maria Caulfield) sharing campaign literature, a conspiracy theory featuring in that guide, relating to 15-minute cities, which is closely linked to antisemitism and far-right movements?

“Ms Caulfield just last week gave a staunch defence of her actions showing no contrition for the damage she has caused.”

Ms Mordaunt thanked Sir Lindsay for his statement before criticising Ms Powell for her remarks about Ms Caulfield, saying: “I’m sorry that she’s made the comments she has and implied that she has antisemitic views.

“I think that is quite wrong and I’m afraid is pattern of behaviour of inciting unpleasant things. We’ve seen it this week following, I’m afraid, Monday’s vote which has led to the statement that the Speaker has had to make.

“I’m very pleased that we brought that motion forward, the work that the Commission did and that we now have a scheme in place.

“I’m sorry that all members did not have the opportunity to vote on that final motion and I’m very sorry that one of the results of the debate and what has followed is that our environment has become less safe for certain members, ironically female Members of Parliament, following some of the actions that have happened since that debate took place.”

Ms Caulfield later said she had pointed to “rumours about 15-minute cities” in a letter to her Lewes constituents more than a year ago about a council consultation on “15 to 20-minute communities”.

But Ms Caulfield criticised the suggestion she was a “conspiracy theorist” and highlighted the “death threats and abuse” she has received while serving as vaccines minister.

She added: “More importantly, then to be linked to antisemitism when my family are actually Jewish, in London, and have had a very, very difficult time over the past few months, was devastating to be honest.”

Ms Powell replied: “I did not say nor imply that she was herself either a conspiracy theorist or indeed antisemitic, and I do not believe she is either of those things.”