Parts of the UK continue to swelter in a heatwave as forecasters warn of dangerously high temperatures in the coming days.

As parts of south-east England saw the mercury hit 31C on Tuesday, the Met Office issued an updated “amber” extreme heat warning covering July 17 and July 18 for much of England and Wales.

Exceptionally high temperatures are expected to peak on Monday, with south-eastern areas of the UK seeing them climb in excess of 35C, and locally into the high 30s. High temperatures may last into Tuesday, the Met Office said.

There is around a 30% chance that the current heat record – of 38.7C set in Cambridge in 2019 – could be broken.

The Met Office’s warning for extreme heat says there could be a danger to life or potential serious illness, with adverse health effects not just limited to the most vulnerable.

There could also be road closures, and delays and cancellations to rail and air travel.

Heatwaves have been made hotter, longer and more frequent by climate change, and experts have warned of the need to adapt homes and cities in the UK for a future of more intense summer heat.

Ambulance services in England are on the highest level of alert and under “extreme pressure”, trusts have confirmed, as difficulties with the hot weather combine with Covid absences among staff and ongoing delays handing patients over to A&E.

Area covered by weather warning for extreme heat Jul 17-18 2022 (PA Graphics)
(PA Graphics)

London Ambulance Service urged the public to support it as the heat continues by only calling 999 in the event of a life-threatening emergency, keeping hydrated and staying out of the sun during the hottest periods of the day.

The Royal Life Saving Society UK warned people about the dangers of trying to cool off in lakes, quarries, rivers and other waterways in the extremely hot weather.

The charity urged people to find lifeguarded swimming sites, to remember that water is often much colder than it looks, not to go too far from shore or swim against currents, and to always take a friend when swimming.

The warning comes as West Yorkshire Police said a 16-year-old boy, Alfie McCraw, from Wakefield, had died after getting into difficulties while swimming in the Aire and Calder Navigation.

Superintendent Nick Smart said it was an “extremely tragic incident” and urged people not to be tempted to cool off in open water as temperatures got even hotter, unless it was a supervised area intended for swimming.

District Station Commander Jimmy Fitt, of West Yorkshire Fire and Rescue Service, added:  “We need people of all ages to be aware of the risks – we know when it’s warm it’s tempting to get into the water, but you must only do it in safe designated areas or the consequences can be fatal.”

On the roads, the RAC recorded a 10% increase in breakdowns on Monday compared with a typical Monday in mid-July, with hundreds of vehicles across the UK not able to function properly due to the heat.

Network Rail is preparing to introduce speed restrictions to reduce the likelihood of tracks buckling as the heatwave continues, which will cause delays to passenger journeys and disrupt freight services.

Warm weather conditions will remain in place for much of the week for the majority of England and Wales, although slightly less hot on Wednesday and Thursday, with temperatures ramping up again late in the week, the Met Office said.

Met Office deputy chief meteorologist Rebekah Sherwin said: “From Sunday and into Monday, temperatures are likely to be in excess of 35C in the South East, although the details still remain uncertain.

“Elsewhere, temperatures could be fairly widely above 32C in England and Wales, and in the mid-to-high 20s further north.”

Downing Street said “significant work” is being done within Whitehall to ensure the most vulnerable are protected during the heatwave.

The Prime Minister’s official spokesman said planning had been taking place within the NHS and with local councils as well as across transport networks.

Hot weather can put a strain on the heart and lungs, with older people, those with pre-existing health conditions and young children particularly at risk.

It can cause dehydration, heat exhaustion or even heatstroke, and affect the ability to work or concentrate.

People are being encouraged to try to keep their homes cool, for example by closing blinds or curtains and keeping bedrooms well ventilated at night, drink plenty of fluids, avoid too much exercise and stay out of the sun during the hottest part of the day.

In some areas, the heatwave comes in the wake of months of below-average rainfall, and water companies are urging households to save water, as demand surges in the face of the high temperatures.

Although hosepipe bans are not currently on the cards, Thames Water and Yorkshire Water are among those warning their reservoirs and other resources are lower than normal.

People are being urged to turn off taps when brushing their teeth or washing dishes, only run dishwashers when full, switch the garden hose for watering cans, reuse paddling pool water for plants, let the lawn go brown and avoid washing cars.