
The rapidly escalating gambling scandal is the latest misfortune to unfold for Sunak, who is forecast to lose power on July 4 after a campaign characterised by gaffes that followed his surprise announcement of an early vote.
The Conservative Party confirmed that campaign director Tony Lee had taken a leave of absence.
The statement on Thursday followed news reports that the Gambling Commission was looking into allegations of improper betting by Lee and his wife Laura Saunders, a candidate for parliament in Bristol.
British bookmakers allow bets on politics, and the timing of an election is a popular bet. But placing bets with insider knowledge is a crime.
"We have been contacted by the Gambling Commission about a small number of individuals. As the Gambling Commission is an independent body, it wouldn't be proper to comment further, until any process is concluded," a Conservative spokesperson said.

London police said on Wednesday that they had arrested a police officer working in a special protection unit over alleged bets made on the timing of the election.
The BBC reported the officer worked as one of Sunak's bodyguards.
A spokesperson for the Gambling Commission said it was investigating "the possibility of offences concerning the date of the election" but could not provide further details at this stage.
"We are not confirming or denying the identity of any individuals involved in this investigation," the spokesperson said.
Senior Conservative minister Michael Gove told LBC Radio it was "beyond bad to use insider information like that to secure an advantage".
Polls forecast the Conservatives are set to lose the July 4 election, potentially in an historic wipeout.
Sunak's party was already far behind in the polls when he announced the election, and has failed to narrow the gap after a campaign marred by blunders, including a decision by Sunak to leave early from a ceremony for the anniversary of D-Day.
I think the answer lies in who the real string-pullers are. The top brass of both Labour and Conservatives serve the Globalist agenda.
The polls [Link] and recent by-elections show that Labour, although assured victory over the Tories, is also losing to Libs, Reform and the likes of Galloway's Worker's Party.
I would bet that the word has come down from The City of London, Zurich etc. - "Do it now before the plebs toss both of you!"