Brits baking in 40C temperatures this week may face problems should they need to call for help as phone networks are set to crash in the record-breaking heat.
An amber warning initially covers all of England on Sunday andextends to southern Scotland and Wales from Monday until Tuesday.
The danger is cranked up in some areas of the nation on Monday and Tuesday when a red warning for heat- the first ever issued- comes into effect.
The Met Office has warned the near-unbearable heat will cause issues for most of the population, warning it is not just those with underlying conditions who could suffer.
Phone networks are also feared to struggle as the mercury explodes with forecasters claiming the UK’s record of 38.7C from 2019 is set to be beaten.
The Met Office said: “There is a high risk of failure of heat-sensitive equipment, potentially leading to localised loss of power and mobile phone services.”
Experts Cornwall Insight said: “Increased temperatures can increase degradation of transformers and overhead lines, which could lead to failure.”
The Met Office earlier issued a danger to life health alert during the worst of the heat and are urging people to look out for vulnerable friends and family members with those who have heart and breathing problems most at risk.
Met Office spokesman Grahame Madge said: “If people have vulnerable relatives or neighbours, now is the time to make sure they’re putting suitable measures in place to be able to cope with the heat.
“This is a very serious situation.”
To prepare for the coming days the NHS has more staff on alert should people struggle in the stifling heat.
Heat exhaustion and dehydration are a likely threat to the elderly, babies and young children.
Some routine hospital appointments and surgery, scheduled for tomorrow and Tuesday, have been postponed to reduce the risk to frail patients travelling into hospital and to free up capacity for extra emergencies.
Tracy Nicholls, chief executive of the College of Paramedics, told Sky News’ Sophy Ridge on Sunday people could die in the heatwave should ambulances struggle to cope.
She said: “It’s difficult not to call it a crisis – it’s been a stealth crisis.”
“It’s not that people aren’t going to turn up. It’s just that the system is not enabling paramedics, emergency department staff to do exactly what they want to do, which is look after everybody.”
“This isn’t like a lovely hot day where we can put a bit of sunscreen on and go out and enjoy a swim and a meal outside.
“This is serious heat that could actually ultimately end in people’s deaths because it is so ferocious.
“And we’re just not set up for that sort of heat in this country.”
The heat is also set to cause nightmares for commuters with rail networks and the London Overground warning of delays as speed restrictions will be brought in to protect passengers.
Those not making urgent journeys have been told to stay away if possible.
Jake Kelly, Network Rail’s system operator group director, said: “Rail passengers in England and Wales should only travel if necessary on Monday and Tuesday as there will be delays and cancellations to train services due to the unprecedented heat we’re expecting.”
Climate attribution scientist at the Met Office, Dr Nikos Christidis, said: “We hoped we wouldn’t get to this situation but for the first time ever we are forecasting greater than 40°C in the UK.
“In a recent study we found the likelihood of extremely hot days in the UK has been increasing and will continue to do so during the course of the century, with the most extreme temperatures expected to be observed in the southeast of England.
“Climate change has already influenced the likelihood of temperature extremes in the UK.
“The chances of seeing 40°C days in the UK could be as much as 10 times more likely in the current climate than under a natural climate unaffected by human influence.
“The likelihood of exceeding 40°C anywhere in the UK in a given year has also been rapidly increasing, and, even with current pledges on emissions reductions, such extremes could be taking place every 15 years in the climate of 2100.”
Experts have also urged people to avoid alcohol in the baking conditions.