LONDON (AP) — The Latest on Britain's Dec. 12 election campaign and its impending departure from the European Union (all times local):

12:40 p.m.

As Britain's election campaign officially kicks off, a British Cabinet minister has resigned over allegations concerning a former aide's role in a collapsed rape trial.

Alun Cairns says he is quitting as Welsh secretary because of "speculation" surrounding the "very sensitive matter," which is under investigation.

Cairns had denied knowing that Conservative Party staffer Ross England made claims about a victim's sexual history when he was a witness in the 2018 trial, causing the trial to collapse. But the BBC says it has a document showing Cairns was aware of it.

In a resignation letter to Prime Minister Boris Johnson, Cairns said he would cooperate fully with an investigation "and I am confident I will be cleared of any breach or wrong doing."

The news is an unwelcome distraction for Johnson, who on Wednesday is launching the Conservative Party's campaign for Britain's Dec. 12 election.

9 a.m.

British Prime Minister Boris Johnson compared his main rival to Soviet dictator Joseph Stalin on Wednesday as he prepared to officially launch the governing Conservative Party's campaign for the Dec. 12 election.

While unofficial campaigning has been gearing up for weeks, the five-week election campaign formally began when Parliament was dissolved Wednesday. Johnson went to Buckingham Palace to notify Queen Elizabeth II before kicking off the Conservative campaign with a speech in central England.

Election season got off to an ill-tempered start, as Johnson accused the main opposition Labour Party of planning to "raise taxes so wantonly" that it would destroy Britain's prosperity. Writing in the Daily Telegraph, Johnson accused the left-of center party of attacking the rich "with a relish and vindictiveness not seen since Stalin persecuted the kulaks."

Labour leader Jeremy Corbyn, meanwhile, has labelled Johnson's economic plans "Thatcherism on steroids," in reference to the free-market, low-spending ideology of the late former Conservative Prime Minister Margaret Thatcher.

Follow AP's full coverage of Brexit and British politics at https://www.apnews.com/Brexit