Insults, talk of “treason and traitors”, and references to the second world war must be removed from the Brexit debate, say moderate Conservative MPs attempting to curb politicians’s increasingly inflammatory rhetoric.

Despairing at the way some MPs are willing to say anything that will go viral on social media and earn attention, they are asking colleagues to sign up to a code of conduct to stop the worst excesses.

The move comes after Mark Francois, Tory MP for Rayleigh and Wickford and pro-Brexit European Research Group member, said “up yours” in a radio interview to chancellor Philip Hammond in cabinet.

The second world war has been raised on several occasions. Daniel Kawczynski, Tory MP for Shrewsbury and Atcham, recently complained that an “ungrateful EU” had not considered the fact the Britain “helped to liberate half of Europe”.

A senior police officer has raised concerns about the language being used. Martin Hewitt, chairman of the National Police Chiefs’ Council, said that politicians should not “inflame” tensions created by Brexit. Several politicians have also complained of the stress they are facing as a result of the Brexit process.

The text of a pledge is due to be finalised after a meeting on Monday of the new 50-strong One Nation caucus of Tory MPs formed to counter the ERG, but it will commit signatories to acting even-handedly, respectfully and generously.

Nicky Morgan, the former education secretary who is on the group’s board, said the code of conduct was intended to “return normal debate to the airwaves”.

“We are living through unprecedented times, with many members unable to spend as much time with the families as they would like to and it’s not at all helpful to everyday hear people – albeit a minority - competing to be the loudest and boldest,” she said. “So today the One Nation Caucus will pledge that all members will engage only in constructive, polite and respectful discourse.

“In particular, I think we need to drop all the references to world war two – politics has always been full of ‘battle ready’ language which just isn’t the way most people talk anyway. But in the current climate, it simply encourages those listening to talk about treason and traitors, which adds to the toxic nature of the debate.

“We hope this is the beginning of a change in tone at Westminster and invite all members to sign our pledge.”