The shopworkers’ union says it fears the Prime Minister’s energy plan will ultimately be “too little too late”.

Usdaw general secretary Paddy Lillis said the union’s members could not afford to bare the brunt of any emergency aid package.

He said: “We will await the PM’s plan for energy bills, but fear that these will be too little, too late.

“We urge the Government to freeze the energy price cap as an immediate measure, but they must ensure that the costs of this are not passed on to consumers in the longer term.”

Liz Truss is set to finalise a multi-billion package to freeze energy bills, with a source confirming a report in The Times stating the cap will be frozen around the £2,500 mark.

That is more than £500 above the current price cap but £1,000 less than the limit due to be imposed in October.

The plan is based on the current £1,971 energy price cap plus the £400 universal handout announced under Mr Johnson’s government.

But the suggestion is that the potentially £150 billion package would be funded by Government borrowing.

Help is also expected for business customers struggling with soaring bills which are not covered by the existing energy price cap in England, Scotland and Wales.

In her first speech as Prime Minister on Tuesday, Ms Truss insisted the nation can “ride out the storm” caused by Russian leader Vladimir Putin’s war in Ukraine.

“After twelve years of Conservative rule and a summer of zombie government, we are totally underwhelmed by what we heard from Liz Truss today,” Mr Lillis said.

“Our members were desperate to hear the new Prime Minister lay out a substantial and urgent plan to tackle the cost of living crisis, which would stem rocketing energy prices and bring inflation under control.

“They wanted to see a commitment to bring forward an employment bill that will end poverty pay and insecure work.

“However, instead we heard little to help the lives of working people struggling to make ends meet and her number one priority is tax cuts for the rich.”

Mr Lillis urged the Government to adopt Labour’s proposals for a six-month freeze on energy bills at the current £1,971 price cap, funded in part by expanding the windfall tax on oil and gas profits.

“It appears we are destined for more of the same until we can get a general election and a Labour Government. That cannot come too soon,” Mr Lillis said.

“The new PM would have done much better to adopt Keir Starmer’s plan for an energy price cap freeze that will help protect against future price shocks, along with Labour’s New Deal for Workers. Only Labour has the plans to help the country through the cost of living emergency.”