oris Johnson will miss a crisis meeting on the response to the heat wave because he is throwing a farewell party at his estate.
The With Office issued a warning of extreme heat amid fears that rising temperatures could cause health problems and even deaths.
Experts have warned that there is likely to be a life-threatening situation as large parts of the country swelter below temperatures of 41 degrees on Monday and Tuesday.
A third COBRA meeting on the matter, chaired by the Duchy of Lancaster Kit Malthouse, is expected to take place over the weekend.
But Boris Johnson will be with Checkers and reportedly unable to attend the meeting, Sky News reported.
Checkers, Buckinghamshire, the Prime Minister’s Official Country Home (Steve Parsons/PA)
/ PA archiveMr Johnson will host a party on Sunday to thank loyal MPs, aides and No10 staff before a new prime minister is proclaimed on September 5.
Angela Rayner, deputy Labor leader, condemned Mr Johnson for being “missing”.
Ms Rayner said: “Boris Johnson is missing in action again. He’s back to his old tricks of skipping important COBRA meetings.
“Where is the plan for the delivery of essential services and how to keep people safe at work, on transport, in schools, hospitals and care homes?
“The public will not be confident that this zombie conservative government is responding quickly and decisively to this national emergency as this disgraced Prime Minister prepares to feast while Britain cooks.
“If he still can’t take responsibility for the job, he should leave now.”
No10 has been contacted for comment.