A heat-health alert has been issued as soaring temperatures saw the UK officially record its warmest day of the year so far.
The Met Office said that at 2.46pm on Wednesday the thermometer reached 32.6C (90.7F) at London’s Heathrow Airport.
It warned that conditions could get hotter still later in the afternoon.
Forecasters expect temperatures to reach around 33C (91.4F) in some parts of the country and people are being warned to take care in the sun.
The Met Office raised the level to three on Wednesday, as health authorities encouraged those most vulnerable – many of whom have been shielding during the lockdown – to protect themselves amid the “exceptionally hot weather forecast this week”.
Public Health England (PHE) said older people, those with underlying health conditions, and very young children were all more at risk from the higher temperatures.
The amber level three, which is currently in place for the West and East Midlands, requires social and healthcare services to target specific actions at high-risk groups, according to the Met Office website.
People have been advised to keep cool and stay hydrated where possible.
The mercury is expected to hit the low-30s in the south of England before Friday and warnings have been issued about UV levels, which are going to be “exceptionally high” over the next few days.
Emer O’Connell, consultant in public health at PHE, said it was important that people kept checking on the vulnerable, as many continued to spend more time at home due to coronavirus.
“You will need to do things differently this year, for example keeping in touch by phone,” she said.
“If you need to provide direct care to someone at risk from hot weather, follow Government guidance on how to do this safely.
“The most important advice is to ensure they stay hydrated, keep cool and know how to keep their homes cool.”
Shoppers have also been advised to be aware they could be forced to spend extra time in the sun as a result of social distancing measures.
Dr Lynn Thomas, Medical Director at St John Ambulance explained: “You could end up in the sun for longer than expected on what would normally be a quick journey, such as queuing to enter the supermarket, so you should be prepared to look after yourself and others.”
She added: “Heat exhaustion and heatstroke are two of the most serious problems that can develop when the mercury soars but by being prepared you can spot the early warning signs, such as headache and dizziness.”
Beaches were busy on Tuesday as people took advantage of the good weather after the months of lockdown spent at home.
Tuesday was not quite the hottest day of the year, as the 28.6C recorded at Heathrow Airport and Kew Gardens fell short of the 28.9C recorded at the end of May.
Advice from the Met Office included closing curtains on rooms that face the sun to keep indoor spaces cooler, avoiding excess alcohol and dressing appropriately for the weather.