UK Prime Minister Boris Johnson extended his lead over opposition Labour Part leader Jeremy Corbyn as he strengthens the ruling Conservatives’ grip on working-class voters ahead of the December 12 general election, according to new poll.

This week’s Deltapoll survey for The Mail on Sunday gave the Conservatives a 15-point lead, up from 12 points last week, with the ruling party on 45 per cent and Labour on 30 per cent.

Johnson now will need to pick up a string of Labour-held seats in northern working-class areas if he is to return to Downing Street with a healthy majority.

The poll suggested that his clear pro-Brexit policy, unlike Corbyn’s contortions on the issue, were winning him support in the Leave-backing areas.

Last week, PM Johnson had launched his Conservative Party’s campaign, who is facing an unprecedented candidate against him. A young Muslim immigrant Ali Milani  who represents the Labour Party in Uxbridge and South Ruislip constituencies of northwest London.

But if the Labour leader puts in an unexpectedly strong performance during the televised Election debates, starting with his head- to-head showdown with Johnson on ITV on Tuesday night, it could give him a boost.

Johnson is hopeful that the December 12 election will break the long impasse over Brexit and give his party a majority so he can extricate Britain from the European Union.

The revolt by Nigel Farage’s Brexit Party candidates – many of whom pulled out of contests rather than risk splitting the Conservative vote in key marginals – has left his party marooned on 6 per cent, according to the poll.

The poll  further suggested that most voters thought Farage’s political career was nearing its end: a total of 45 per cent said his most successful days were behind him, and just 11 per cent said they were ahead of him.

Meanwhile Johnson, 55, was born in New York and his father was a diplomat, who served in Brussels for a time, and his mother an artist. He was educated at Eton and Oxford. Before entering politics, he was a celebrity journalist.

The two candidates are at extreme poles from their family background to culture to their political ideologies.

Deltapoll interviewed 1,526 British adults online between November 14 and 16.

If Johnson lost his Uxbridge seat, this hasn’t happened to a prime minister in modern times, then he would probably step down, Travers said. The party could try to create a sudden vacancy and stage a one-off election for one seat, “but there’s always a risk that the electorate won’t like that. . . . It’s hard to see him getting back into Parliament until there was a naturally occurring by-election.” In theory, Johnson could attempt to run his administration from the House of Lords, but that hasn’t happened since the premiership of Robert Gascoyne-Cecil more than a 100 years ago.

(With inputs from agency)