Rishi Sunak may face another difficult byelection after an MP lost his appeal against a 35-day suspension from parliament for offering to lobby ministers on behalf of the gambling industry.

Scott Benton, the MP for Blackpool South, formerly a Conservative, had asked for a reconsideration of the standards committee verdict that he had committed an “extremely serious breach of the rules”.

Benton had offered to lobby ministers on behalf of the gambling industry and leak a confidential policy document for up to £4,000 a month, which the committee found merited a suspension of 35 days, subject to a parliamentary vote.

Undercover reporters for the Times posing as representatives of a fake investment fund had approached the MP, who told them he could “call in favours” from colleagues and get “easy access” to ministers when queueing for parliamentary votes.

The Commons standards committee said at the time that the message he gave to the undercover reporters was “that he was corrupt and ‘for sale’, and that so were many other members of the house”.

“He communicated a toxic message about standards in parliament. We condemn Mr Benton for his comments, which unjustifiably tarnish the reputation of all MPs.”

Benton appealed on the grounds that the procedure was flawed, claiming the decision was leaked by the committee. This was dismissed by the independent expert panel, which hears challenges to the watchdog’s findings.

If the Commons backs the punishment, it could leave Benton – who was stripped of the Conservative whip after the allegations surfaced – facing a byelection.

Blackpool South is one of the “red wall” seats, having backed the Labour party from the 1997 election until Benton’s win in 2019. It is one of the most deprived areas in England.

Labour has selected the leftwing trade unionist Chris Webb as its prospective parliamentary candidate for the seat, which Keir Starmer’s party believes it can win.

A party spokesperson called on Benton to resign immediately rather than wait for the outcome of any recall petition.

Jonathan Ashworth, the shadow paymaster general, said: “Scott Benton should do the decent thing and resign, saving the people of Blackpool South a lengthy recall petition that would leave them without the representation they deserve.

“This is yet another byelection caused by Tory scandal. Britain deserves better than this carousel of Conservative chaos.

“Labour’s Chris Webb is Blackpool born and bred, and ready to deliver a fresh start for Blackpool South.”

Labour has comfortably won byelections in Wellingborough, Kingswood, Rutherglen, Tamworth, Selby, Wakefield and Mid Bedfordshire in recent times.

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