The Tories have been boosted by a “Boris bounce” after the election of their new leader, according to a poll.
Since Boris Johnson became Prime Minister after being declared party chief by Tory members, the Conservatives have gained 10 points to stand at 30%, a survey by Deltapoll for the Mail on Sunday showed.
That puts them five points ahead of Labour at 25%, with the Liberal Democrats on 18% and the Brexit Party on 14%.
But if Labour were to drop Jeremy Corbyn as leader, the poll says the party would shoot into the lead at 34%, with the Tories on 28%, the Brexit Party on 14% and the Lib Dems on 13%.
Ahead of the 2017 snap general election, polls suggested Labour were as much as 20 points behind the Tories just weeks before votes resulted in a hung parliament.
The survey by Deltapoll comes as Mr Johnson set out an eye-catching domestic stall promising a £3.6 billion boost for left-behind towns as he sought to shift the political spotlight from Brexit.
The PM also pledged funding for a major new rail link between Manchester and Leeds, and promised action on housing and crime, despite insisting he was not preparing for a snap autumn election.
Mr Johnson said: “I want to be the PM who does with Northern Powerhouse Rail what we did with Crossrail in London.
“And today I am going to deliver on my commitment to that vision with a pledge to fund the Leeds to Manchester route.
“It will be up to local people and us to come to an agreement on the exact proposal they want – but I have tasked officials to accelerate their work on these plans so that we are ready to do a deal in the autumn.”
Downing Street said detailed plans regarding the proposed rail route will be published in the autumn, following a review into HS2.
The trans-Pennine route is expected to cut journey times and provide additional capacity for people across the region.
The Mail on Sunday poll also found that opinion was evenly divided on the question of whether Mr Johnson’s partner Carrie Symonds should live with him at Number 10.
While 33% backed such a move, the same number were opposed to it.
Asked how they would feel if Mr Johnson married their daughter, 57% said they would be sad, while 16% said they would be happy.
Other polls showed a similar boost in support for the Tories since Mr Johnson’s election as leader.