The Brexit Delivery Group, which represents about 100 Remain and Leave MPs, is calling for a free vote in the Commons to take no deal off the table in a major challenge to the prime minister, according to The Telegraph.
Tory MPs Andrew Percy and Simon Hart, who lead the parliamentary group, have written a letter to chief whip Julian Smith that many MPs are "deeply troubled" at the prospect of no deal, Presstv Reported.
"We are a loosely aligned group and we have been very consistent as a group in support of the prime minister's deal but in that scenario dozens of my colleagues have made clear to us that they would want to vote in a way that would prevent a hard no-deal Brexit,” the letter says.
"A lot of colleagues are becoming very frustrated, a lot of colleagues have compromised from their positions,” it said.
But former Tory leader Lord Howard rejected the calls for a delay to Brexit and insisted fears about a no-deal departure from the EU had been "exaggerated".
Some senior British ministers have also warned May that she must agree to delay Brexit if there is no European Union divorce deal.
Work and Pensions Secretary Amber Rudd, Justice Secretary David Gauke, Business Secretary Greg Clark and Scotland Secretary David Mundell said she must take no deal off the table by extending Article 50, The Sun newspaper reported Thursday.
If May refuses, the senior ministers said they and 20 other members of the government would back Labour lawmaker Yvette Cooper’s plan for parliament to seize control of the Brexit process.
Brexit Secretary Stephen Barclay and Attorney General Geoffrey Cox announced they will hold talks again with EU chief negotiator Michel Barnier in the coming days on the Northern Ireland backstop.
May believes that securing legally binding guarantees on the backstop is key to getting her Withdrawal Agreement through the Commons.
The backstop arrangements would see the whole of the UK remain in a customs union with the EU and Northern Ireland following some single market rules until a wider trade deal is agreed, in order to prevent the need for checkpoints on the Irish border.