A coalition of charities and health experts has called for an overhaul of the UK’s “broken” sick pay system, as the number of people prevented from working by long-term sickness reached a record high. The group urged the health secretary, Steve Barclay, to support changes that it says would not just address widening health inequalities but also benefit the economy. Figures released on Tuesday morning by the Office for National Statistics (ONS) showed the number of people across the UK who are economically inactive because of long-term sickness is a record 2.5 million, up 400,000 since the start of the Covid-19 pandemic. It will be difficult to achieve the aims of the government’s recent “back to work” budget without a healthy workforce who are supported when they get ill, says a letter to Barclay coordinated by the Safe Sick Pay campaign. “Our sick pay system lags behind the rest of Europe,” says the letter, whose signatories included the chief executives of Mind, the Centre for Mental Health, the Business Disability Forum and Prof Jim McManus, the president of the Association of Directors of Public Health. For the UK to come into line with international standards, they call for changes including the abolition of the earnings threshold for statutory sick pay (SSP) – a change that would help workers including those with a number of jobs – along with making SSP payable from the first day of sickness and increasing it to be in line with a worker’s wages up to the “real living wage”. The issue is particularly pertinent for lower- and some middle-income workers. An estimated 8 million people only have access to a below-subsistence level of £1.10 an hour sick pay in the first week and £3 an hour thereafter. “Workers are encouraged to either leave employment or go back to work before they are fully better,” says the letter. “The strain of coping with illness coupled with the financial hit can also exacerbate mental health problems and can tip people into a mental health crisis. The result is widening health inequalities.” The charities and experts draw attention to the nearly 2 million people such as cleaners, carers and parents juggling childcare or multiple jobs, who they say are “slipping through the cracks” and get no sick pay at all. In parliament there is an unusual degree of cross-party support for calls to overhaul the sick pay system. The backbench Tory MP Jonathan Gullis used prime minister’s questions to press the case for reforms that he said had broad support from businesses, and proposals are also being discussed by Labour. Gullis told the Guardian he was looking forward to meeting the chancellor Jeremy Hunt to press for sick pay reform in the autumn statement. Gullis said he and fellow Conservative MPs Priti Patel and Robert Buckland would meet next month with the Centre for Progressive Change thinktank and the chancellor, Jeremy Hunt, to press for sick pay reform in his autumn statement. He added: “With over 75% of British businesses responding to a government survey saying they support change to sick pay, the chancellor has clear road ahead of him to make these important reforms, improve the health of our workforce and help grow the economy.” While campaigners are eager to see what commitments make it into the Labour manifesto, Keir Starmer talked at the recent annual conference of the GMB union about “statutory sick pay for all”. Speaking about carers, he said: “For many of them, every time they had to self-isolate during the crisis, they did so at their own expense, with no sick pay. That’s not on.” The Safe Sick Pay campaign cites research indicating that improved access to paid sick leave can help increase employee retention, with one study of cancer patients suggesting employees covered by paid sick leave were three times more likely to return to work. Charities including Young Lives vs Cancer have joined the campaign because of what they regard as the disproportionate effect on cancer patients from current SSP arrangements. The charity says young people and parents have spoken of the difficulties of accessing SSP for reasons including the terms of contracts, the types of jobs they are in or because they are in part-time or insecure work. The Department of Health and Social Care and the Department for Work and Pensions have been approached for comment.