Margot James says she is prepared to quit government along with other Tories

The digital minister, Margot James, has urged the prime minister to rule out the “catastrophe” of a no-deal Brexit, warning that she and other ministers are ready to resign if the prime minister refuses.

James, together with fellow ministers Richard Harrington and Claire Perry, called on the government to extend article 50 to avoid leaving the EU with no agreement on 29 March.

Speaking to BBC Radio 4’s Today programme, she said: “All of us are agreed that we couldn’t be part of a government that allowed the country to leave the European Union without a deal.”

Asked if this meant they were ready to quit, or be sacked, James said: “If it comes to that, yes.”

But James said she was hopeful Theresa May would offer concessions, including an extension to article 50, in a statement she was due to give to the parliament on Tuesday.

In that statement, May is expected to make a last-ditch attempt to avoid a cabinet rebellion before a vote on Wednesday on a cross-party amendment laid by the Conservative Oliver Letwin and Labour’s Yvette Cooper that would in effect rule out a no-deal Brext.

The prime minister’s most likely option is a pledge to let MPs vote on delaying Brexit for a short time if she does renegotiate her withdrawal deal and win support for it before 12 March.

James said: “We don’t know what the whipping is going to be [or] what the prime minister is going to say in parliament today. We have got every reason to hope that things will progress more smoothly.”

In an article in the Daily Mail, writing with Harrington and Perry, James signalled the group’s support for the Cooper/Letwin amendment.

They wrote: “It is a commitment that would be greeted with relief by the vast majority of MPs, businesses and their employees. We implore the government to take that step this week.

“But if the prime minister is not able to make this commitment, we will have no choice other than to join MPs of all parties in the House of Commons, including fellow ministers, in acting in the national interest to prevent a disaster in less than five weeks’ time that we may regret forever.”

There is mounting speculation that up to 15 ministers could be prepared to join them as patience among MPs opposed to no deal is stretched to breaking point.

James told Today: “For quite a long time colleagues and I have been very concerned about the way in which this deal, which the prime minister is trying to get through, is continuously be frustrated … As D-day approaches we felt honour-bound to do something to help prevent such a catastrophe.”

She added: “By making this stand, hopefully that will encourage others to come in and support that deal and get it through. That’s our primary goal.”

“If for any reason we can’t persuade enough colleagues to get in behind that deal then it is so near to 29 March that the only option going forward is to extend article 50.

“I don’t think any of us want to see that happen but I think we feel that if the deal doesn’t get through then that has to be the alternative; otherwise this country leaves without a deal which none of us wants and there’s a parliamentary majority against that.”

And in a swipe at the hardline pro-Brexit European Research Group, James added: “For us to leave with the biggest trade deal we have got in pursuit of other trade deals that might take 10 years to negotiate with far smaller countries is madness.”