Labour – with the backing of a former Conservative minister, the Scottish National party, the Liberal Democrats and the Greens – will launch the first step in an audacious attempt to block a new prime minister from forcing through a no-deal Brexit.

What is the new bid to prevent no deal?

Labour has tabled a cross-party motion that would hand control of the parliamentary agenda to MPs on Tuesday 25 June. If the motion passes, MPs will have the chance to introduce measures, including legislation, that could help avoid a no-deal Brexit at the end of October.

Who is supporting the measure?

The party will use an opposition day debate – scheduled for Wednesday – to attempt to pass the motion, which has the backing of opposition parties including the SNP, Plaid Cymru, the Liberal Dems and the Greens. The Tory MP Oliver Letwin, a key mover behind bids to block no deal in March, has also pledged support.

Why has Labour tabled this motion to set aside a date?

Labour says the motion is the next step in parliament preventing no deal, putting in place a process to legislate against a new prime minister pursuing a no-deal Brexit on 31 October.

The date of 25 June would ensure this process is in place before the end of the Tory leadership contest, and before MPs leave for parliament’s summer recess.

Does this motion prevent no deal?

No, it does not do anything more than give more parliamentary time for MPs to find a legal route to stop no deal. It gains control of the Commons order paper on 25 June and will give priority to a debate on that day on legislation relating to Brexit.

Parliament can then specify a future date to give consideration to legislation to help prevent no deal on 31 October, similar to the process parliament used prior to the 29 March deadline.

Will Tories back the move?

Letwin is the only Conservative name on the motion but it is understood to have support from remain-backing Tories including the former attorney general Dominic Grieve and the former Tory MP Nick Boles, who quit the party earlier this year.

Steve Baker, the deputy chair of the hard-Brexit European Research Group, said Tories including Letwin were risking the chance of a general election that could result in the Conservatives being wiped out by the Brexit party.

What could be done to stop no deal if the motion succeeds?

There are no details about the plan yet and it remains the legal default that the UK will leave – deal or no deal – on 31 October.

Some MPs, including the Lib Dem leadership candidate Ed Davey, have suggested making it the legal default that a prime minister should revoke article 50, rather than leave without an agreement. However, it is unlikely such a radical move could garner the necessary cross-party backing.