The prominent Remain-backing MP Ben Bradshaw has urged colleagues not to break away from the Labour Party in an interview with LabourList.

The former Culture Secretary, now a leading supporter of the ‘People’s Vote’ campaign, confirmed reports that he told party colleagues on a pro-referendum WhatsApp group not to “do something silly” and walk away, following last night’s refusal by the Labour leadership to back an amendment demanding a year-long extension of Article 50.

He called for the whip to be enforced against Labour MPs who voted for Theresa May’s Brexit deal – and warned of an ‘exodus’ of Labour members unless the leadership backed a fresh referendum.

Speaking to LabourList, Mr Bradshaw rejected calls for a split: “My very strong view is that everybody’s efforts at the moment need to be focused on getting us out of this Brexit nightmare and ensuring the party leadership honours our unanimously agreed conference motion.

“It’s clear there can’t be a general election in the next six weeks, and Theresa May has rejected Corbyn’s softer Brexit offer. The party must move now to implement our policy which is a public vote.”

Putting pressure on the Labour leadership, Mr Bradshaw told this site it was unthinkable that Jeremy Corbyn could continue to resist calls for a so-called ‘People’s Vote’.

“It’s inconceivable to me that Jeremy – who has based his whole leadership on party democracy and listening to members would renege on our agreed policy. If that happened it would cause uproar.”

Following reports of a mass walkout of members over the party’s Brexit policy, Mr Bradshaw said he was “very worried” about an ‘exodus’.

The MP for Exeter refused to comment directly on MP colleagues’ discussions regarding a ‘Valentine’s Day split’, but said: “A lot of [party] members are hanging on because they’re hoping Jeremy will not betray them.”

Much hinges on the next few weeks and whether Article 50 will be delayed. The backbencher said the party would ‘potentially have more time’ to clarify it’s Brexit position were there an extension.

But he warned against dithering: “The public and party members are looking for firm leadership at this very perilous time in our country’s history.”

When asked about fears that backing second referendum could leave to a collapse in Labour’s support in Leave-backing areas, the Exeter MP added: “All the polling evidence shows Labour would suffer huge damage if we are complicit in or enable a Tory Brexit.

“Most Labour voters in [Leave-backing] seats voted Remain and the swing since the referendum has been most marked in the seats that voted leave. It’s a time for those MPs to do what is in the country’s best interests.”

Commenting on the four Labour MPs who voted for Theresa May’s Brexit statement on Thursday night, he suggested disciplinary action could be considered. “It’s very disappointing, but it emphasises how important it that the whip is properly enforced.

“Many members and MPs were concerned two weeks ago when the whip on the Cooper-Boles amendment [attempting to rule out no deal] was not enforced – in contrast to when those who broke the whip to vote for a customs union and the single market were sacked or asked to resign.”

While refusing to call for the whip to be withdrawn from Leave-backing Labour backbenchers, Mr Bradshaw added: “We do need to have some consistency.”

Pro-EU MPs have long been angry over the apparent discrepancy between the leadership’s treatment of Remainer rebels compared to Leaver rebels.

The prominent Remainer also avoided suggestions Remainers could lay an amendment for a second referendum in coming weeks. “It’s certainly getting very late to table and vote on a public vote amendment. We can’t wait to the end of march to do so…The immediate priority is to take no deal off the table. If May won’t do that herself, Parliament has to do that for her.”

“Given that all the other options in Labour’s policy are now exhausted, I don’t see what’s holding the front bench up of going for a public vote.”

On Thursday night another prominent Labour Remainer, Chris Leslie, said backbenchers were “being played for fools by the leadership” over Corbyn’s refusal to back a fresh public vote.

Asked whether he agreed, Ben Bradshaw said: “I’m not as pessimistic as Chris. But if that doesn’t happen, there will be uproar in the party.”

Josiah Mortimer is editor of Left Foot Forward and is covering Sienna while she’s away.