Proroguing the House of Commons to achieve a no-deal Brexit would be “the end of parliamentary democracy” in the UK, Dominic Grieve has said in defending his move to seek to remove the option.

Grieve’s amendment, which has cross-party support including from a handful of fellow Conservative MPs, is to the Northern Ireland bill going through the Commons, and would require fortnightly reports on that country’s formation of an executive, which has been vacant since 2017.

Speaking on the BBC Radio 4 Today programme, Grieve said the amendment calls for “regular motions before parliament in September and particularly October”. If passed, it would prevent the parliamentary session being prorogued, or abruptly ended, in the lead-up to the 31 October departure date.

Q&A What does 'prorogue parliament' mean? Show Hide Prorogation is the official term that marks the end of a parliamentary session. After being advised to do so by the prime minister, the Queen formally prorogues parliament. This takes the form of an announcement in the House of Lords on the Queen’s behalf. It is a speech, written by the government, which usually describes the bills that have been passed during that session and summarises what has been achieved. It means that all work on existing legislation stops, and MPs and Lords stop sitting. Prorogation also automatically kills any bills, early day motions or questions to ministers going through parliament. Parliament can then be reopened a few days later with a fresh slate of legislation intentions, set out in a new Queen’s speech at the formal state opening of parliament.

Grieve, a former attorney general, said “the idea that it is constitutionally proper to prorogue parliament as a device for bringing about a no-deal Brexit is outrageous … I have never come across a more extraordinary suggestion.

“If you decide that parliament is an inconvenience, when in fact it is the place where democratic legitimacy lies in our constitution, and therefore it’s acceptable to get rid of it for a period because it might otherwise [stop] you from doing something that parliament would prevent, then it’s the end of democracy.”

Boris Johnson, the frontrunner to replace Theresa May and become the new prime minister, has said he is not in favour of prorogation, telling the Daily Mail: “I’m not attracted to archaic political devices.” Grieve noted, however, that the “this extraordinary idea crept in” during the course of the leadership election and Johnson “seemed to adopt it”.

“It should be denounced by anybody who is planning to be the prime minister of a democratic country,” Grieve said, and Johnson “should be saying very, very clearly that there’s no possibility of proroguing parliament to achieve an aim of the executive”.

He said whoever became prime minister in a country “where there are deep divisions over Brexit, where the party he is leading does not have a majority in the House of Commons and is dependent on the support of another minority party” should either call a general election or “govern taking into account the opinion of the Commons”.

“To try to simply disregard that opinion and to try to pretend it doesn’t exist is to court disaster.”

If MPs made a stand today to prevent prorogation, it would mean they could avoid having to do something more drastic later, Grieve said.

Grieve was backed by the Conservative former foreign secretary William Hague, who told Today: “I think it’s very important that parliament is able to give its opinion. It ought to be unthinkable that we could leave the EU by a manoeuvre, by a procedural ruse of some kind.

“While I don’t agree with everything Dominic has said or tried to do, I sympathise with attempts to ensure that parliament can have its say.”

Opponents of the amendment, such as the Tory MP Steve Baker, who is one of the leaders of the hardline European Research Group, expressed outrage that Theresa May might give Tory MPs a free vote on the amendment.

“Incredibly, I understand there is some doubt about the whipping on this matter.” Baker tweeted. “Surely Theresa May won’t allow her legacy to include failing to resist dragging the Queen into politics?”

He later drew attention to a newspaper story which suggested the chancellor, Philip Hammond, would support May’s legacy projects if she gave Tory rebels opportunities to vote for measures that ruled out a no-deal departure from the EU.

“What a way to govern a country,” Baker tweeted.