The majority of voters in the Conservatives' most marginal constituencies believe Theresa May's Chequers plan is "bad for Britain", a new poll has found as critics warned it is now more hated than the poll tax.

A survey of 22,000 voters in the Conservatives' 44 most marginal seats found that three-quarters of people are "dissatisfied" with the Government's handling of Brexit negotiations.

Over half of those polled believe the policy is "bad" for Britain, while just 21 per cent believe it is "good". The poll found that Brexit is considered more important in the marginal constituencies than the NHS and the economy.

On Monday the Prime Minister faced a mounting backlash from both Leave and Remain Tory MPs after Boris Johnson, the former foreign secretary, branded Chequers a "disaster" in an article for The Telegraph.

Downing Street hit back at Mr Johnson on Monday, saying he offered "no new ideas" while Mrs May is offering "serious leadership and a serious plan".

However, Justine Greening, a Tory MP and prominent Remainer who is calling for a second referendum, says she agrees with Mr Johnson as she warns Chequers is now less popular than the poll tax.