One in five people said that Boris Johnson and the Conservatives would be most responsible if Britain did not leave the EU on October 31

Boris Johnson has failed to sell his Brexit deal to the public with undecided voters turning against it, a poll for The Times suggests.

Only 19 per cent thought the agreement struck with Brussels last week was a good deal, according to the survey by YouGov, and only 3 per cent said it was a “very good deal”.

However, 34 per cent said they did not know enough about the agreement to offer an opinion, down from 45 per cent a week ago, with most of those who had made up their minds deciding that the deal was either bad or indifferent.

According to 28 per cent the deal is bad, up five percentage points, and 20 per cent thought it was neither good nor