THERESA May’s bid to get Tory MPs to back her Brexit plan suffered a new blow yesterday when a poll suggested more than half of Conservative Party members would prefer a no-deal withdrawal from the EU than what the Prime Minister has come up with.

In a three-way choice, 57% of grassroots Tories said they would support leaving the EU without an agreement, while 23% would back the Prime Minister’s deal and 15% would choose to remain. A total of 5% had no preference.

The poll also suggested a two-way referendum would see 29% of Tory members endorse the PM’s stance, with 64% choosing a no-deal Brexit.

The research was carried out by YouGov for the Party Members Project, which studies membership of the UK’s six biggest parties and is funded by the Economic and Social Research Council.

After May suddenly pulled a vote on the Withdrawal Agreement last month because it faced a significant defeat, MPs will begin debating the proposals again next Wednesday with a vote scheduled for the following week.

Professor Tim Bale of Queen Mary University of London, who led the research said: “If Theresa May is hoping that her MPs will return to Westminster having been persuaded by their constituency associations to back her Brexit deal, she’s going to be disappointed.

“It appears that those members are in no mood for compromise. Moreover, the Tory rank and file, it seems, are convinced that no deal is better than May’s deal.”

Bale suggested there were two specific issues behind the opposition to May’s deal, the first being the Irish backstop. “Tory members have become convinced that the Irish backstop is a bad idea,” he said, citing statistics that 40% think it is a reason in itself to reject a deal, and 21% think it is irrelevant because May’s deal “is a bad one anyway”.

Bale added: The second issue is that 76% of members believed warnings that a no-deal Brexit would cause serious disruption are “exaggerated or invented”.

“In short, Mrs May has failed not only to convince the country, and quite probably Parliament, that her Brexit deal is a good one, she has also failed to convince the party faithful.”

The poll findings came as May’s Brexit agenda suffered a series of new blows.

As Democratic Unionist Party deputy leader Nigel Dodds insisted his party’s opposition to Irish border backstop proposals had not lessened, Irish Taoiseach Leo Varadkar insisted there could be no changes to the backstop, which is intended to prevent a hard border in Ireland by ensuring the UK abides by EU customs rules if no trade deal is agreed by the end of a Brexit transition period.

Varadkar said he had spoken to German Chancellor Angela Merkel by phone on Thursday and the two leaders agreed to “stand by” the Brexit deal. He said: “We’re happy to offer reassurances and guarantees to the UK, but not reassurances and guarantees that contradict or change what was agreed back in November.”

As the EU closed ranks, the European Commission confirmed “no further meetings are foreseen” with the UK on updating May’s Brexit deal because negotiations have concluded.