British Chancellor of the Exchequer Jeremy Hunt watches, as Prime Minister Rishi Sunak hosts a PM Connect event at Siemens Healthineers in Eynsham, Oxfordshire, Britain, May 10, 2024.

British finance minister Jeremy Hunt on Thursday said it would be "very tough" for the Conservatives to win the July 4 election, after opinion polls predicted a landslide win for the opposition Labour Party.

On another chaotic day for the governing party, its campaign director took a leave of absence, which media reports linked to an investigation around bets being placed on the date of the election before it was announced.

Polls indicate Britain is on course to elect a centre-left Labour government led by Keir Starmer, ending 14 years of rule by the Conservatives, whom many voters blame for political and economic turmoil that has lowered their living standards.

Asked at a Times newspaper event whether the Conservatives could win the election, Hunt said: "It's going to be very tough.

"I don't think any of us would pretend that is the most likely outcome. We can certainly do a lot better than the polls are suggesting and we are working very hard to do so."

Starmer is set to walk into the prime minister's office at 10 Downing Street with a 200-seat parliamentary majority, the biggest for any party for a century, according to the latest poll by YouGov.

A separate poll predicted Rishi Sunak could become the first British prime minister in history to lose his own seat in a national election. Hunt's seat is also under threat.

Sunak's party was already far behind in opinion polls when he called the election, hoping that an upturn in economic data would help it narrow the gap with Labour.

But that has failed to materialise from a Conservative campaign beset by missteps, starting with Sunak's bedraggled announcement of the election in pouring rain, and most notably his leaving D-Day commemorations in France earlier than other world leaders, for which he apologised.

The latest embarrassment was a Gambling Commission investigation into a second Conservative candidate over bets placed on the timing of the election. The BBC named the candidate as Laura Saunders and said her husband, campaign director Tony Lee, was also being investigated.

"The Director of Campaigning took a leave of absence from CCHQ yesterday," the Conservative Party said in a statement. Neither Lee nor Saunders could immediately be reached for comment and the gambling regulator did not name those it was investigating. Placing bets with insider knowledge is a crime.