LONDON: Former prime minister Boris Johnson made a surprise appearance in the British election campaign on Tuesday, issuing a last-ditch bid to rally support for the Conservatives and their leader Rishi Sunak, the man who helped turf him out of office.

Johnson won a big majority at the last election in 2019 before being forced to resign in 2022 by a Conservative mutiny which Sunak helped to start, and which exposed deep splits in the governing party, not least between Sunak and Johnson.

Greeted by chants of "Boris! Boris!" from party supporters two days before an election which the Conservatives are predicted to lose heavily, he introduced the current prime minister at a campaign event in London.

In a speech listing many of his own achievements, Johnson gave little personal endorsement to Sunak but focused on what he said were the dangers of the opposition Labour Party winning power.

"None of us can sit back as a Labour government prepares to use a sledgehammer majority to destroy so much of what we have achieved," he said.

Acknowledging that some might be surprised to see him, he said he was glad to be asked to help by Sunak. "Of course I couldn't say no," he added.

"Whatever our differences they are utterly trivial by comparison with the disaster we may face if these so-called opinion polls are right," Johnson said.

Johnson, one of British politics' most recognisable figures and a proven election winner, has spent almost the entire campaign on the sidelines, having quit frontline politics in 2023. He has endorsed individual candidates in video messages but has not previously appeared at big campaign events.

Sunak, who appeared after - but not alongside - Johnson on the stage, thanked his predecessor.

"Isn't it great to have our Conservative family united, my friends?" he said.