Daisy Cooper has ruled out a future bid for the Liberal Democrat leadership and backed Sir Ed Davey after the resignation of two frontbenchers fuelled speculation of a potential contest.

The deputy leader insisted the party was going “from strength to strength” under Sir Ed despite reports of internal frustrations about its lack of progress since the 2024 election that saw it secure a record 72 MPs.

Witney MP Charlie Maynard quit as a Lib Dem Treasury spokesman earlier this month days after Mid Sussex MP Alison Bennett, a former care and carers spokeswoman, also stood down from her role.

Neither has publicly commented on the reason for their departure though Mr Maynard is reported to have asked parliamentary colleagues to back a vote of no confidence in the leader.

Asked about MPs losing faith in Sir Ed as the party lags behind Labour, the Tories and Reform UK in the polls, Ms Cooper told a press conference: “Ed is our most successful leader ever in the history of our party.

“And the last general election proved that we have been underestimated time and time and time again…  for as long as we have first-past-the-post, the national polls do not translate into winning seats, and we have proven that under Ed Davey’s leadership we can transfer votes into seats like no other political party.

“And for as long as we have first-past-the-post that has to remain the goal.

“So not only are we determined to retain the seats that we won at the last general election, but we know that we are going to win more seats at the next general election, and we’ll continue to go from strength to strength.”

She suggested the Lib Dems’ “environmentalist, internationalist” platform was receiving less attention on social media, where “a lot of the conversation is happening” because of “algorithms” favouring extreme politics.

“We’re not going to adopt an extreme position just to get the online clicks, and I think people will appreciate that,” Ms Cooper said.

The Lib Dems became the third largest party in Westminster at the last election but has since gained little ground in the polls, with the latest YouGov survey putting the party on 12% – the same as their share in 2024.

Asked whether she could rule out a tilt for the top job in the future, she said: “Yes I can. I’m not going to be launching any leadership bid at all.

“I really enjoy being deputy leader to Ed. We work incredibly well as a team, and I’ve got a lot of work to do as Treasury spokesperson, not least next week when I hold the Government to account on their Budget.”

In her speech on Monday, Ms Cooper called on the Government to announce a £14 billion “breathing space” budget to ease the cost of living, including through a 10p cut to fuel duty, a 10% cut to rail fares, £1 bus fares and a reduction in VAT on kerbside electric vehicle charging to 5%.

The party has also proposed an “essential energy guarantee” which it says would reduce average annual electricity and gas bills by £100, alongside additional support for households with children and disabled people.

Hospitality VAT would also be slashed by five percentage points to 15% under the proposals, which the Lib Dems say could be funded by measures including a one-off windfall tax on the “unexpected and unearned” profits of big banks, and a “clawback” of profits made by energy-network firms.

Ms Cooper said: “Families are facing a brutal double whammy of rising bills and disappearing support. Energy costs are set to go up again, filling up the car keeps getting more expensive, and household budgets are being squeezed from every direction.

“The Chancellor has a choice. He can stand by as families are hit with yet another cost-of-living squeeze, or tax the huge unearned windfalls enjoyed by the big banks and use that money to give people some breathing space.

“Our £14 billion emergency package would cut energy and transport costs and give struggling high streets a fighting chance. It would mean cheaper bills, cheaper journeys and a bit more money left over at the end of the month.

“People shouldn’t have to think twice about taking their children out for a meal or meeting friends at their local pub because the basics have become unaffordable. The Chancellor should use this Budget to put money back into people’s pockets and give people the breathing space they’re crying out for.”