Showdown: David Cameron and Boris Johnson criss-crossed the country as they campaigned yesterday

Some 44 per cent said it made them more likely to vote to quit the Brussels club – outstripping the claim by Project Fear that leaving is a leap in the dark.

In a slew of other polls, Leave either led or the contest was neck and neck. The ComRes poll for the Mail reveals Britain is a divided country with over 45s and those in the North breaking heavily for Leave.

All age groups below 45 appear in favour of staying with 64 per cent of those aged 25 to 34 wanting to stay and 27 per cent opting to go. Among the 55 to 65 age group, however, just 31 per cent want to Remain and 55 per cent want to Leave.

In the South 38 per cent want to Leave while 51 per cent want to stay. But in the North, it is 41 per cent Remain and 50 per cent Leave. The Midlands is almost exactly balanced with 45 per cent support for Remain and 44 per cent for Leave.

Overall, after 'don't knows' are counted, Remain would lead 54 per cent to 46 per cent. The poll of 1,032 adults was conducted over the weekend, during part of which the campaign was halted after the murder of the Labour MP Jo Cox.

Some 17 per cent say that they may still change their mind.