Britain’s Prime Minister Boris Johnson sits on a train in London, Friday Dec. 6, 2019, on the campaign trail ahead of the general election on Dec. 12. File photo: Peter Nicholls/Pool via AP.

LONDON – British Prime Minister Boris Johnson said he was nervous about his narrowing lead in opinion polls ahead of Thursday’s election but pledged to deliver a “transformative” Brexit on Jan. 31 that would allow lower immigration.

The Dec. 12 election will decide the fate of Brexit and the world’s fifth largest economy with a stark choice between Johnson’s pro-market Conservatives and the socialist-led opposition Labour Party.

“Brexit is the most radical and profound change to the management of this country,” Johnson told Sky, adding that he would lead the United Kingdom out of the EU on Jan. 31 if he won a majority in the 650-seat parliament.

“Brexit is indispensable – you can’t move forward without Brexit,” said Johnson, the face of the ‘out’ campaign in the 2016 referendum who won the top job in July after Prime Minister Theresa May failed to deliver Brexit on time.

Voting begins at 0700 GMT on Thursday and polls close at 2200, when an exit poll will give the first indication of who has won. Johnson will likely need more than 320 seats to ensure he can stay prime minister and ratify the Brexit deal he struck in October.