A senior minister is at risk of being suspended from the House of Commons after Labour and the Democratic Unionist party were allowed to submit an emergency motion accusing the government of holding parliament in contempt for failing to publish the full Brexit legal advice.

John Bercow, the Speaker, allowed Labour, the DUP and four other opposition parties to lay down a motion that will be voted on on Tuesday, immediately before before the start of the five-day debate on the Brexit deal.

Conservative MPs were put on a three-line whip on Tuesday morning – to prepare to defend the government against a contempt vote.

Ahead of the vote, the transport secretary, Chris Grayling, a former lord chancellor, was defiant. “It is a central part of the principles of our legal system that the advice provided from a lawyer to their client is treated as confidential. It’s privileged information,” he told BBC Radio 4’s Today programme.

“Do we really want to undermine one of the most sacrosanct parts of the way our legal system works? In this particular case for the government, I think that would be the wrong thing to do.”

The contempt motion, submitted late on Monday, calls on MPs to find “ministers in contempt for their failure to comply” and is signed by the shadow Brexit secretary, Sir Keir Starmer; the DUP’s Westminster leader, Nigel Dodds; and the Scottish National party, Liberal Democrats, Plaid Cymru and the Green party.

No penalty is spelled out in the motion, which is intended to act as a final warning, but Labour said that if it was passed on Tuesday and still not complied with then the party would seek further sanctions.

Labour indicated it would then seek to hold a senior minister – likely to be either the Cabinet Office minister, David Lidington, or the attorney general, Geoffrey Cox – in contempt and seek their suspension from the Commons.

However, Labour sources said their priority remained getting the legal advice published, rather than forcing a minister to be punished.

Bercow ruled late in the evening that he would accept a contempt motion after the six parties wrote to him jointly complaining that the summary Brexit legal advice released on Monday did not comply with a Commons resolution agreed on 13 November.

The Speaker declared on Monday night that there was “an arguable case that a contempt has been committed” after Labour and others complained that “the information released today does not constitute the final and full advice provided by the attorney general to the cabinet”.

Panicked Conservatives flooded the Commons chamber late into the evening to filibuster a debate on Scotland’s foreign policy footprint, to give their party’s whips time to submit their own amendment to the contempt motion.

Downing Street declined to respond on Monday night, but the governing party put down an amendment seeking to refer the matter to the Commons privileges committee, in an attempt to kick it into the long grass.

A Labour source said the government motion, submitted by Andrea Leadsom, “implicitly accepts they are in contempt but seeks to play for time before the meaningful vote”, calling it disrespectful to parliament.

The Speaker accepted the plea from the combined opposition parties after a fractious two-and-a-half-hour debate in which Cox repeatedly refused to release the full legal advice on the Brexit deal he had provided to cabinet.

The row is likely to overshadow the first day of the five-day debate, which May intends to lead in her increasingly fraught attempt to get her Brexit deal endorsed by parliament.

Cox conceded in Monday’s debate that he was at risk of being declared in contempt of parliament for his actions when he became the first attorney general for 40 years to appear before MPs to take questions.

The government’s chief legal officer said MPs must decide “whether or not an attorney general, seeking to protect the public interest” was in contempt. He said he had “sought to comply with the spirit of it to the maximum degree” by putting himself before MPs and publishing a 45-page summary earlier in the day.

Ominously for May, some hard-Brexit MPs said they were unsatisfied by the decision to defy an earlier Commons resolution calling for full publication.

Jacob Rees-Mogg accused Cox of not explaining why ministers were refusing to comply with the Commons motion. “It is no longer a matter for the government to judge; it has been decided by this house, which is a higher authority,” he said.

On 13 November, the Commons unanimously agreed to a motion put down by Labour calling for the legal advice on the Brexit deal to be published “in full”. Conservative MPs were told to abstain after it became clear that the government was not certain of winning the vote when the DUP said it would vote with Labour.

Cox told the Commons on Monday that the government had made a mistake at the time. He said: “We should have opposed it,” although he added that he would not have complied even if the vote had been lost.

Steve Baker, the former Brexit minister who has been a spokesman for the party’s Eurosceptics, hinted at a way out for Cox. He queried why the government had not accepted an amendment to the original Labour motion, tabled by Tory MPs, which was “highly sympathetic” to Cox’s position.

Asked whether he would consider bringing a new motion to avoid a contempt vote, Cox suggested that was under consideration.

The government’s chief lawyer sought to sell the Brexit deal to MPs on the grounds that it represented “a calculated risk”.

The attorney general admitted he would have preferred to have seen “a unilateral right of termination” in the controversial Northern Ireland backstop and “a clause that would have allowed us to exit if negotiations had irretrievably broken down”.

Downing Street had hoped to start persuading backbenchers to support May’s deal despite widespread concern in her party that the UK could become trapped in the backstop. May spoke with small groups of backbench MPs in her Commons office throughout the day.

On Tuesday, the prime minister will open the five-day debate leading up to the final vote next week by saying that the British people have already twice voted to deliver Brexit.

The prime minister will argue that the British public showed what they wanted “by voting overwhelmingly for parties that committed to delivering Brexit” in the referendum and in the 2017 election Both Conservative and Labour manifestos at the last election said they respected the leave vote in the 2016 referendum.

Tuesday’s debate will be closed by the Brexit secretary, Stephen Barclay, and the following days will be themed, with senior cabinet ministers speaking in support of the deal.

Wednesday’s theme will be security, and the debate will be opened by the home secretary, Sajid Javid, and closed by Jeremy Hunt, the foreign secretary. On Thursday, the focus will be on the economy, opened by the chancellor, Philip Hammond, and closed by the international trade secretary, Liam Fox.