British Prime Minister Boris Johnson is heading to northern England on Saturday to meet newly elected Conservative Party legislators in the working class heartland that turned its back on the opposition Labour Party in this week's election and helped give him an 80-seat majority.

In a victory speech outside 10 Downing Street on Friday, Johnson called for an end to the acrimony that has festered throughout the country since the divisive 2016 Brexit referendum, and urged Britain to "let the healing begin."

Johnson's campaign mantra to "get Brexit done" and widespread unease with the leadership style and socialist policies of opposition leader Jeremy Corbyn combined to give the ruling Conservatives 365 seats in the House of Commons, its best performance since party icon Margaret Thatcher's last victory in 1987. Labour slumped to 203 seats, its worst showing since 1935.

While Johnson was on a victory lap Saturday, Corbyn — who has pledged to stand down early next year — was under fire from within his own party.

Prime Minister Boris Johnson fought the election under the slogan of 'Get Brexit Done,' promising to end the deadlock and spend more on health, education and policing. (Dan Kitwood/Getty Images)

Former legislator Helen Goodman, one of many Labour legislators to lose their seat in northern England, told BBC radio that "the biggest factor was obviously the unpopularity of Jeremy Corbyn as the leader."

Armed with his hefty new majority, Johnson is set to start the process next week of pushing Brexit legislation through Parliament to ensure Britain leaves the EU by the Jan. 31 deadline. Once he's passed that hurdle — breaking three years of parliamentary deadlock — he has to seal a trade deal with the bloc by the end of 2020.

Concern over immigration

Johnson owes his success, in part, to traditionally Labour-voting working class constituencies in northern England that backed the Conservatives because of the party's promise to deliver Brexit. Traditional Labour voters in the north and central parts of England deserted the party in droves. During the 2016 referendum, many of those communities voted to leave the EU because of concerns that immigrants were taking their jobs and perceived neglect by the central government in London.

Early in the campaign, pundits said the election would turn on these voters, who were dubbed the "Workington man" after the one-time steel-making community in northwestern England. The Conservatives won Workington on Thursday by more than 4,000 votes. The constituency had supported Labour candidates since 1918, with only one short interruption in the 1970s.

"I think that people have lost hope in Labour," said Nicki Lawal, 24, who lives in London's Brixton neighbourhood.

PM won by leaning left and right

Mathew Goodwin, a professor of politics at the University of Kent, said Johnson matched a bit of leaning to the left on the economy with a similar lean to the right on Brexit, migration and crime.

Watch | What Boris Johnson's win means for the U.K. and its allies:

Boris Johnson’s landslide election victory will push Brexit forward, which will have ripple effects on the increasingly fractured United Kingdom and for Britain’s allies. 6:55

Johnson "appears to have grasped one of the new unwritten laws in politics: It is easier for the right to move left on economics than it is for the left to move right on identity and culture," he wrote on his blog.

The question now is whether the Conservatives can address the economic and social concerns of these voters and hold on to their support in future elections.

Conversely, some traditionally Conservative-supporting communities in southeastern England flipped to Labour as the pro-EU sentiments of middle class voters outweighed other issues.

Scotland the next flashpoint

Johnson's election win comes after a 3½-year political deadlock over Brexit, that has effectively paralyzed business in the U.K. Parliament. Johnson is asking the British people to put anger behind them. But with about half of Britain wanting to remain in the European Union, and nationalist sentiment rising in Scotland and Ireland, unity will not be easy.

Jeremy Corbyn’s Labour party lost large swaths of its traditional territory in the Dec. 12 vote, which left the Conservatives with the largest majority since Margaret Thatcher’s third-term victory in 1987. (Leon Neal/Getty Images)

The next flashpoint for U.K. politics may be Scotland, where the Scottish National Party won 48 of the 59 seats that were up for grabs on Thursday.

SNP leader Nicola Sturgeon delivered the landslide victory with a campaign focused on demands for a second referendum on Scottish independence. Johnson has flatly rebuffed the idea of another vote, saying Scotland already rejected independence in 2014.

Sturgeon argues that the U.K.'s decision to leave the EU against the wishes of the Scottish people has materially changed the landscape. Some 62 per cent of Scottish voters backed remaining in the EU during the 2016 referendum on membership.

Scottish leader drawing up transfer of power plan

"It is the right of the people of Scotland. And you, as the leader of a defeated party in Scotland, have no right to stand in the way," she said. She plans to publish a detailed case next week for a transfer of power from London that would clear the way for a second Scottish independence vote. Scots voted in 2014 to stay in the UK.

However, Johnson told Sturgeon by phone on Friday he opposed another referendum, prompting Sturgeon to say her political mandate must be respected, "just as he expects his mandate to be respected."

In Northern Ireland, supporters of a united Ireland won more seats than those in the province who want to remain part of the United Kingdom for the first time since the 1921 partition which divided the British north from the Irish Republic in the south.

Buying more time with EU

Several hundred noisy protesters marched through central London on Friday evening to protest against the election result, disrupting traffic and chanting "Boris Johnson: Not My Prime Minister" and "Boris, Boris, Boris: Out, Out, Out."

Johnson's sweeping success will give him room to manoeuvre on such issues, particularly involving the fraught details of Brexit. Jim O'Neill, chair of the Chatham House think-tank , said the size of the Conservative Party victory gives it a clear mandate to execute the first stage of departing the EU by passing the withdrawal bill.

It also allows the government to "explore its future trade relationship with the EU with more time" and extends the transition period, he said. "Even more importantly, in principle, this majority gives the prime minister the leeway to be bold and reveal his true desires for both domestic and global Britain."

'Impossible' for PM to meet promise of EU talks

After Jan. 31, Britain will enter a transition period when it will negotiate a new relationship with the remaining 27 EU states. The outcome of those talks will shape the future of its $3.5-trillion economy.

Scottish National Party, under leader Nicola Sturgeon, is the third most powerful bloc in the U.K. Parliament, behind Labour and the Conservatives. On election night, she said Johnson does not have a mandate to take Scotland out of the EU. (Jeff J Mitchell/Getty Images)

The transition period can run until the end of December 2022 under the current rules, but the Conservatives made an election promise not to extend it beyond the end of 2020.

It will be "absolutely impossible" to negotiate terms of an exit in only one year, said Scotland's Brexit Secretary Michael Russell. He told CBC News on Saturday that the Comprehensive Economic and Trade Agreement (CETA) between Europe and Canada took seven years to hammer out.

Russell said holding a referendum on Scottish independence is a "sensible step forward" because Brexit will be financially damaging.

Watch | Michael Russell advocates for a Scottish referendum on independence:

Michael Russell, Scotland's Brexit secretary, says it's imperative that Scotland hold a referendum on independence 0:40

German Chancellor Angela Merkel said many within the EU were relieved that Britain would now have a Parliament with a clear majority, highlighting the frustration that European leaders have felt during three years of political logjam in London.

But she said it would be "very complicated" to complete the talks on a new relationship by December 2020.

French President Emmanuel Macron warned Britain on Friday that the more it chose to deregulate its economy after Brexit, the more it would lose access to the EU's single market.

U.S. President Donald Trump congratulated Johnson and said a U.S. trade deal could be more lucrative than any with the EU, the world's biggest trading bloc. "Celebrate Boris!" Trump said on Twitter.