Rishi Sunak's election campaign has gone from bad to worse as a rapidly escalating gambling scandal becomes the latest misfortune to mar the Conservatives.

Multiple figures within Mr Sunak's orbit have become embroiled in an investigation around alleged bets on the timing of the election.

Here's how the saga has unfolded, and what it means for polling day.

What happened?

Last week it emerged Craig Williams, who is standing for a parliamentary seat in Wales, bet 100 pounds ($190) that Mr Sunak would call an election for July, just days before he did.

Mr Williams stood to win 500 pounds ($950).

It was a surprise to both politicians and voters when Mr Sunak announced Britons would head to the polls on July 4, as many had expected an autumn (September–December) election.

Asked whether he had placed the bet based on inside information, Mr Williams told the BBC: "I clearly made a huge error of judgement, that's for sure, and I apologise."

Who else is involved?

A few days later, one of Mr Sunak's security guards was arrested over alleged bets on the timing of the election.

The scandal erupted further when Britain's gambling regulators revealed they were investigating a second Conservative Party candidate, Laura Saunders.

Ms Saunders is running for a seat in the south-west English city of Bristol.

Critically, she's also married to the party's campaign director, Tony Lee.

Now, just two weeks out from the election, Mr Lee has stepped aside.