Boris Johnson has urged voters to back the Tories amid speculation he might appear on the General Election campaign trail.

A spokesman for the former prime minister said he was “as always, strongly supporting the Conservatives” and “encourages everybody to do the same” following the announcement that a poll would take place on July 4.

But it remains unclear whether Mr Johnson would join Rishi Sunak or other candidates on the campaign trail, despite months of speculation about his plans for the election period.

On polling day itself, Mr Johnson will hope not to repeat his experience at May’s local elections, when he was turned away from a polling station after attempting to vote without a valid photo ID.

Meanwhile, Mr Sunak’s direct predecessor Liz Truss said she looked forward to campaigning for re-election in South West Norfolk.

Britain’s shortest-serving prime minister tweeted a statement saying she would be “running on my record of standing up for local residents over the past 14 years”.

She added: “Only by returning a Conservative MP on 4th July can residents be guaranteed a strong voice for South West Norfolk in Westminster who has a track record of fighting for lower taxes, controlling our borders and traditional conservative values.”