Ministers will hold an emergency Cobra meeting on Saturday after meteorologists warned of record high temperatures in England that could put lives at risk.
Cabinet Office minister Kit Malthouse is to chair a meeting of the Government’s Cobra civil contingencies committee to discuss the escalating heatwave, a Government spokesman said.
It will be the second Cobra meeting Mr Malthouse has led on the issue.
Meteorologists have given an 80% chance of the mercury topping the UK’s record temperature of 38.7C set in Cambridge in 2019, with the current heatwave set to peak on Tuesday.
Following the issuing of the Met Office’s first red warning for extreme heat, covering a swathe of England from London to Manchester and York on Monday and Tuesday, its chief executive Penny Endersby said people can find it hard to to know what to expect when “climate change has driven such unprecedented severe weather events”.
“Here in the UK we’re used to treating a hot spell as a chance to go and play in the sun,” she added.
“This is not that sort of weather.”
Temperatures will climb over the weekend, and the Met Office has also issued an amber warning for heat covering all of England, southern Scotland and Wales from Sunday until Tuesday.
London Mayor Sadiq Khan held a special meeting with key senior officials from agencies including the NHS, the Met Police, London Fire Brigade, London Ambulance Service, councils and Transport for London on Friday to ensure there is a robust plan in place to deal with the level four heat alert.
Mr Khan has urged Londoners to undertake only essential travel on Monday and Tuesday and to prepare for disruption because speed restrictions will be in place on rail and Tube networks.
A high air pollution alert for London has also been issued by the mayor for Monday.
Labour meanwhile criticised Prime Minister Boris Johnson after reports said he had failed to attend Cobra meetings.
Angela Rayner, Labour’s deputy leader, said: “Boris Johnson has gone missing in action again. He’s back to his old tricks of skipping important Cobra meetings.
“Where’s the plan for the delivery of essential services and how people will be kept safe at work, on transport, in schools, hospitals and care homes?
“The public will have no confidence in this zombie Conservative government responding swiftly and decisively to this national emergency as this disgraced Prime Minister prepares to party while Britain boils.”
Daytime temperatures on Saturday are predicted to be around 27C in London, 26C in Cardiff, 23C in Belfast and 21C in Edinburgh.
On Sunday, it could reach 30C in the capital, 27C in Cardiff, 24C in Belfast and 23C in Edinburgh.
Temperatures are forecast to increase by several more degrees on Tuesday – up to the mid-30s for much of England and Wales.
There is a 50% chance of temperatures reaching 40C somewhere in the UK, likely along the A1 corridor which runs from London to Scotland through counties including Lincolnshire, Nottinghamshire, Yorkshire and the North East, with the Met Office issuing its first ever red warning for extreme heat.
The UK Health Security Agency has increased its heat health warning from level three to level four – a “national emergency”.
Level four is reached “when a heatwave is so severe and/or prolonged that its effects extend outside the health and social care system… At this level, illness and death may occur among the fit and healthy, and not just in high-risk groups,” it said.
Britons have meanwhile been scrambling to buy fans and looser clothing to help them keep cool during the heatwave.
Retailer Toolstation said sales of fans have risen by 641% over the last week compared with the week before as tradespeople struggle to stay cool.
The company also said sales of builders’ shorts have increased by 50% and t-shirts by 35%.
Fire brigades, including South Wales Fire And Rescue Service, Scottish Fire And Rescue and London Fire Brigade, have issued safety warnings, urging people to act responsibly.
They warn people to disposing of barbecues, lit cigarettes and glass bottles responsibly, to not burn any rubbish such as garden waste and use local authority services instead, and that barbecues should not be used on balconies or near sheds, fences, trees, shrubs and garden waste to avoid anything catching alight.
They also urge people who are cooling off in waterways to be aware of cold-water shock.
