Members of the “chaotic, irresponsible” Government have been accused by Labour leader Sir Keir Starmer of “fighting like cats in a sack” amid the energy crisis.

Earlier, in a U-turn, Chancellor Kwasi Kwarteng agreed to bring forward his proposals setting out his medium-term fiscal plan alongside Office for Budget Responsibility (OBR) predictions to October 31.

Meanwhile, Prime Minister Liz Truss has been attempting a charm offensive to bridge the divides blighting the Conservative Party as she faces mounting pressure to raise benefits in line with inflation.

Sir Keir, who was touring boiler and heat pump manufacturer Vaillant’s head office in Belper, Derbyshire, said: “We’ve got an energy crisis, a security crisis, we’ve got to deal with our obligations to meet the climate crisis.

“I think that’s not just an obligation, it’s the single biggest opportunity for the next generation of jobs.

“I’ve come to see that for myself, and to explain how a future Labour government will work with business, where we set the mission with clarity and work with business to achieve that.

“Frankly if we had seen more of that in the last 12 years we wouldn’t be in the appalling position we’re in now, because this Government has not insulated homes in the way it should have done, hasn’t developed nuclear and renewables.

“It has caused – or made worse – an energy crisis that of course is caused, in part, by the international conflict.”

He repeated calls for the Government to reverse its “kamikaze mini-budget”, also introducing a windfall tax on oil and gas firms “to pay for the energy price freeze”.

Sir Keir said: “What that will do – and most important of all – is to stabilise the economy, because this chaotic, irresponsible approach is all of the Government’s own making.”

Asked whether the Government was being “sensible” in not making any decision to uprate benefits in line with inflation ahead of an official process, at the end of November, Sir Keir said it had been “totally irresponsible”.

The Labour leader said: “I don’t think it’s for the Government to tell anybody else what’s sensible because they’ve been totally irresponsible.

“They know (and) we know that benefits should be increased in line with inflation.

“Forty per cent of those on benefits are in work, 30% can’t work because of disability.

“I can’t think that any political party can possibly think it’s right to put the most vulnerable in a position where they find it even harder to make ends meet.”

Asked if he was talking directly to Conservative MPs who might seek to join with Labour in voting against measures not to raise benefits by inflation, Sir Keir said “there are always conversations going on across Parliament”.

He added that the Government, “instead of actually taking responsibility and reversing it (the mini-budget), they’re fighting like cats in a sack”.

“I think for the public looking on, who are directly affected by the irresponsibility of this Government, they’ll be aghast.”

Earlier, Sir Keir had been looking around Vaillant’s huge plant, where the firm has been developing emerging technologies such as hydrogen-capable boilers and heat pumps.

The whole-of-UK market for home heating is vast, with 1.6 million boilers per year being fitted or replaced.

The market for heat pumps is also growing, with 60,000 units per year now being fitted in UK homes.

Sir Keir, speaking to the company’s apprentices and technicians, said: “Heat pumps – feels like they are the future?”

Louise Needham, Vaillant head of training, replied: “They’re definitely part of the solution, but they’re no silver bullet.

“We’ve got to find the mix of hydrogen and heat pumps.”

Later, speaking to reporters, the Labour leader said the country had “lost a lot of ground in the last 12 years”, adding the UK was “behind” in areas such as renewables.

He added “solar farms are part of the solution”, but said he “wouldn’t back fracking”, saying it had “a huge impact on local communities which is why they (communities) don’t want it”, “took years” to commercially realise gas deposits, and had little impact on wholesale prices.