Rishi Sunak is facing more electoral pain after it was confirmed there is to be a by-election in a Labour target seat and an opinion poll showed the Reform party moving into third place. 

Former energy minister Chris Skidmore announced he planned to resign the Tory whip and quit the Commons last week in protest at the government’s plans to expand oil and gas drilling.

Mr Skidmore formally submitted his resignation as an MP on Monday and refused to vote for the Government’s Offshore Petroleum Licensing Bill.

The Bill will create annual licensing rounds for oil and gas projects in the North Sea, which the former minister said was a backward step and a distraction from renewable energy.

Boundary changes mean Mr Skidmore’s Kingswood seat near Bristol is due to be abolished at the next election and he had already announced his intention not to stand elsewhere.

However by going early, he leaves the Tories defending an 11,200-vote majority in the constituency, which was held by Labour until 2010.

Mr Sunak also faces a by-election in Wellingborough where the former Tory MP Peter Bone was ousted in a recall petition over disputed bullying and sexual misconduct claims.

The local party selected his partner, Helen Harrison, as their candidate on Sunday.

Mr Sunak refused on Monday to say if he was “proud” of that given her links to Mr Bone.

“Candidate selection is done locally, so local members in their area can choose a given candidate, that’s how it works in our party," he told a PM Connect evebnt in Accrington in Lancashire.

"We believe in empowering people locally, that’s how we do it and that’s the same with all byelections.”

The Tories, who lost four by-elections last year, face a further by-election in the coming months in Blackpool South, where Tory MP Scott Benton faces a possible recall petition.

He is currently appealing a decision of the Standards Committee, which recommended a 35-day suspension after finding he had breached Commons rules by offering to lobby ministers and table parliamentary questions on behalf of gambling investors.

Losses in the contests, followed by expected setbacks in English local elections in May, could provide Mr Sunak with a terrible run-up to the general election in the autumn.

Adding to Tory jitters, the pollsters Redfield & Wilton Strategies put the right-wing anti-migration Reform party in third place for the first time on Westminster voting intention.

Asked how they would vote in a general election tomorrow. 43% of respondents UK-wide said Labour, 27% Tory, 11% Reform and 10% Liberal Democrat.

Although Reform, which was founded by Nigel Farage but is now led by Ricbard Tice, is unlikely to win any seats, it has promised to stand in every mainland constituency, potentially drawing support away from the Tories and helping Labour into power.

The UK’s top civil servant, the Cabinet Secretary Simon Case, also returned to work on Monday following a three-month period of illness, meaning he could now be called to give evidence to the UK Covid Inquiry about his withering views on Boris Johnson.

Mr Case missed a scheduled appearance last year.

WhatsApp messages disclosed to Lady Hallett’s inquiry show that in July 2020, before he became Cabinet Secretary, Mr Case said of Mr Johhnson’s government:  “I’ve never seen a bunch of people less well-equipped to run a country”.

He also described the then Prime Minister and his inner circle as “basically feral”.