The money saving expert Martin Lewis has criticised Liz Truss for failing to come up with a plan to tackle “catastrophic” energy price rises and warned that people will die without help. Reacting to confirmation that the average household energy bill will increase to £3,549, Lewis said: “This is a catastrophe … if we do not get further government intervention, on top of what was announced in May, then lives will be lost this winter.” Lewis expressed exasperation at the government and the two Tory leadership candidates for the absence of any detailed plan to help people cope with the rise. Speaking on BBC Radio 4’s Today programme, he said: “The only thing I’ve heard that gives me some hope is that both candidates have said they understand the need for more help. My frustration is that we haven’t been told in clear details by both candidates, and especially by the candidate most likely to win [Truss], what that help is.” He said ministers and the leadership contenders had done nothing to stop people panicking. “The mental health damage to people across the country alone is catastrophic. This is not good government. It’s not good politics either. I’m just shocked that they haven’t thought we need to have something in place to give people peace of mind,” he said. “If you were to see my social media inbox, the panic, the dismay, the depression – people simply say: how will I afford to eat and feed myself?” Lewis said he could not understand why ministers had delayed announcing a contingency plan. “This is shocking but it is not a surprise. What is staggering is we’ve allowed this announcement to be made. This is within £50 of what we were all predicting. And all we’ve heard is ‘we have to wait for the actual figure’. Why?” Lewis pointed out that the new price cap represents 37% of the state pension and “will be an even bigger proportion” of income for those on universal credit. And he predicted that some high users of energy, such as people with disabilities, could face bills of £10,000. “We are in an absolutely horrendous situation. And it is going to get even worse in January,” Lewis said. The chancellor, Nadhim Zahawi, said he acknowledged that the energy price cap rise “will cause stress and anxiety for many people” and he insisted government “help is coming”. Labour accused the government of a dereliction of duty. The shadow chancellor, Rachel Reeves, said it was appalling that no minister was prepared to appear on TV or radio on Friday to answer questions about the new price cap. Speaking to BBC Breakfast, she said: “The government must act. They must freeze gas and electricity prices through the winter. They should pay for that with an extension of the windfall tax on the oil and gas companies who are making huge profits and use that money to keep bills as low as possible for everybody else. “Ministers are drawing salaries to run the country. And yet they are not here to set up what they’re going to do at a time of huge anxiety and concern for people. That is a dereliction of duty and it is, frankly, appalling.” Reeves also criticised Truss and Rishi Sunak. She said: “The two people who want to be the next Conservative prime minister have been going around the country for the last few weeks setting out their policies on almost everything apart from the biggest issue facing our country right now, which is these astronomical increases in gas electricity prices, on which they’ve got almost nothing to say.” She defended Labour’s plans to freeze bills, after the factchecking charity Full Fact claimed there was £5bn hole in the party’s policy because it failed to account for higher energy use during the winter. Reeves said: “The last time they [Full Fact] factchecked Labour’s analysis they had to withdraw their statement a couple of days later. So I would take that with a pinch of salt. This is a six-month package. And this is fully costed.” The Liberal Democrat leader, Ed Davey, said that the rise in the energy price cap was “nothing short of a catastrophe” for millions of households. “As millions suffer, the Conservatives do nothing. No policy from the government, no plan from Liz Truss or Rishi Sunak. They have no idea how much pain these energy prices will cause our country. They are simply unfit to govern,” he said. Andrew Forsey, the national director of the anti-hunger charity Feeding Britain, said: “Unless significant additional help is offered by the new prime minister, these eye-watering prices will spring a vicious hunger trap, leaving millions of families unable to afford heating or eating.” Sara Ogilvie, the policy director at Child Poverty Action Group, said the new cap would terrify many low-income families. “We know that families with children spend 30% more on energy bills than households without kids, yet government has completely failed to recognise the extra costs facing households with children,” she said.