Most Conservative MPs believe freedom of movement and deference to the European Union’s top court should stop the moment Britain quits, according to polling.
Some 65% of Tories believe that crashing out of the bloc would be better than taking a bad deal, the study found.
Britain will remain subject to the rulings of the European Court of Justice (ECJ) during a transitional period lasting around two years after Brexit, Theresa May said in November.
The Prime Minister also failed to rule out accepting any new regulations imposed by Brussels in the two years after March 2019, even though the UK would have no say in drawing them up.
Some 74% were opposed to freedom of movement continuing during a transition period, according to the research, which was carried out on behalf of the UK in a Changing Europe initiative and the Mile End Institute at Queen Mary University of London.
Around two-thirds of Conservative MPs (65%) agreed that no deal is better than a bad deal, compared with 77% of Labour MPs.
Professor Tim Bale, from Queen Mary University of London, who helped design and conduct the survey, said: “The sheer number of Tory MPs seemingly prepared to countenance crashing out of the EU without a deal is one of the most striking findings to emerge from this research.
“Who knows, though, if push does come to shove, whether they really will refuse a compromise? If they do, then Theresa May could be in some serious parliamentary trouble later on this year.”
The survey also found that nine in 10 Labour MPs believe single market membership is compatible with Brexit.
Leader Jeremy Corbyn has faced accusations the party’s policy on the issue lacks clarity.
Some 89% of Tories believe the economy will get better over the next decade, compared with 23% of Labour MPs.
Professor Anand Menon, director of UK in a Changing Europe, which monitors relations between Britain and Brussels, said: “Brexit presents a stark challenge to the leaderships of both major political parties. Their views are at odds with those of their own MPs.
“This promises to cause significant problems for both Theresa May and Jeremy Corbyn. The Prime Minister, in particular, might face considerable opposition from her own backbenchers when it comes to securing the kind of transitional deal she has indicated she wants.”
– The research was conducted by Ipsos MORI in November and December 2017 on behalf of UK in a Changing Europe together with the Mile End Institute at Queen Mary University of London.
– Interviews were conducted with 105 MPs, face-to-face, and findings are weighted to reflect the composition of the House of Commons.