LONDON — A former Conservative lawmaker who used insider knowledge to place wagers on the date that then-Prime Minister Rishi Sunak would call a U.K.-wide election two years ago pleaded guilty Monday to cheating at gambling.

Craig Williams, who was Sunak’s parliamentary private secretary, was one of more than a dozen people charged in the betting scandal over the timing of Britain’s last general election.

Election gambling is legal in the U.K. and betting on the date the prime minister will set is a popular wager. It’s legal for lawmakers to bet, but not if they rely on inside knowledge.

Sunak surprised many in May 2024 when he set the election date for July 4 when the conventional wisdom was that he would wait until the fall.

The announcement itself was a fiasco as Sunak was drenched in a downpour outside 10 Downing St. and word quickly spread that a handful of people with connections to the party had placed suspiciously timed bets. Six weeks later, the Labour Party swept the Conservatives out of office after 14 years of rule.

Williams, 41, who was in meetings when the election date was discussed, admitted in Southwark Crown Court that he used confidential information to gamble. He placed three bets between 22.50 ($29.80) and 250 pounds ($331), prosecutors said.

Williams, who lost his reelection bid for his seat in Wales, later admitted he placed a 100-pound ($132) bet on a July election days before the date had been announced.

“I committed an error of judgment, not an offense, and I want to reiterate my apology directly to you,” he said in a video posted on social media in June 2024.

Prosecutor Zoe Johnson said three additional charges that Williams denied will be dropped when he is sentenced at a later date.

“He has now accepted by his plea that he used highly sensitive and confidential information to place bets and to profit,” Johnson said.

Other members of the Conservative Party that controlled government at the time and a police officer are among those still facing charges that carry a potential two-year prison term, if convicted.

A dozen defendants pleaded not guilty Monday to cheating at gambling and face trials in September 2027 and January 2028.

The wife of Conservative deputy digital director Anthony Hind also pleaded guilty to cheating at betting. Amy Hind, 35, is due to be sentenced Oct. 23. A charge against her husband for passing information to his wife was dropped.