The government must refocus on more radical ideas to help people with everyday costs such as food, energy, childcare and housing, more than 100 Labour MPs have said in a letter to Keir Starmer.

They made the warning amid fears Labour could lose the next election and will bleed voters to both Reform and parties on the left unless there is a much faster pace of change that puts money directly back in people’s pockets.

The letter launches the new Living Standards group of Labour MPs, which will be spearheaded by eight from the 2024 intake. Speaking to the Guardian, MPs from the group said the government also had to change the way it related to voters, speaking less about growth in the G7 and more about the cost of food.

It aims to submit a slew of ideas on driving down everyday costs to government before the autumn, in an attempt to combat the threat to Labour from both leftwing parties and Reform.

The letter is the latest sign of a more activist parliamentary party ready to push its own ideas to No 10 and the Treasury after the tussle over welfare this month.

In their letter to Starmer, which reiterates support for the prime minister and the government, the 104 MPs said there were welcome efforts to raise incomes via investment in industry and changes to workers rights – but said there should now be a big effort towards also lowering everyday costs.

“Our constituents will ask one question at the next election: did this Labour government make me better off?” it said.

“We have some of the highest electricity, housing, and childcare bills in Europe. This is because we are dependent on natural gas for our power, don’t have enough social homes and the last government failed to invest in the childcare we need … [living standards] is the most important issue to our constituents and the country.”

MPs involved in the group – four of whom sit on the Treasury select committee and most in swing seats – said they also believed a renewed focus on living standards would help rebuild faith among disillusioned voters.

“It’s not just about the electoral challenge, but also about our values,” the group’s convenor, Dr Jeevun Sandher, said.

“Our Labour values are about ensuring everyone can earn a decent life. It’s the difference between us and the other side and how we help people to get there. So it’s about both the political focus and providing the ideas. What more can we do to help people feel it?”

Andrew Lewin, the MP for Welwyn Hatfield, who is on the organising committee, said: “It’s also a little bit less talking about the G7, a little bit more about groceries.”

Sandher, the MP for Loughborough, said the group was motivated by polling that suggested 50% of voters who described themselves as economically insecure had stopped supporting Labour since last July.

“You’ve got young graduate renters going to the Greens because they find their housing costs are really expensive. And you’ve got people in post-industrial areas going to Reform because they’re finding everything else really expensive, as well as finding it difficult to find good jobs. And both sides are pulling the ‘I want radical change’ lever,” he said.

Sandher added that the party made had to make decisive and tangible progress on energy bills, housing and everyday costs. “I think if we don’t have that, then I’m not going to get re-elected. Let’s be honest about it,” he said.

The group said it wanted to maintain a broad ideological composition across both new and longtime MPs, with a significant diversity of seats.

Alongside Sandher and Lewin, MPs on the organising committee include some of the most prominent MPs of the new intake – such as Chris Curtis (Milton Keynes North), Lola McEvoy (Darlington), Graeme Downie (Dunfermline and Dollar) and Yuan Yang (Earley and Woodley). The others are Rachel Blake for the Cities of London and Westminster and Luke Murphy, the Basingstoke MP.

The group plans policy launches on three key areas over the coming month, starting next week on energy bills and followed by childcare and housing. It said each policy would be progressive, helping both low- and middle-class households, improve economic efficiency and increase growth and must be cost-neutral or funded by progressive taxation.

“Even in constituencies which are relatively affluent like mine, there are such deep pockets of deprivation,” Yang said. “All working families across the income spectrum feel like they are being squeezed.”

Lewin said it was clear many people felt they needed to see a much faster pace of change. “There is an anxiety there because things have been so bad for the last 14 years. And even if we see wage growth … we see the savings ratio growing, which shows people do have a bit more but are keeping hold of it,” he said.

McEvoy, who also co-chairs the Labour Growth group with Curtis, said bills and low wages were also taking a huge toll on people’s mental health. “They’re one bill away from crisis and it’s having a massive knock-on effect to mental health,” she said.

“It’s about people’s expectations of what they thought their life would be like and. continuously grafting but can’t seem to keep their head above water.”

Curtis said he believed the focus would also help be a unifying force within the party where there had been divisions over strategy. “For years it has polled as the top issue facing voters. We can have all of these arguments in the Labour party about whether we need to care about voters we’re losing to the Greens, whether we need to care about voters we’re losing to Reform or others.

“But actually right across that voter coalition when you sit down and speak to those voters, they will all say the biggest problem facing their lives is the price of food in the shops.”