Nick Triggle
Health correspondent

At least six NHS trusts in England have declared critical incidents because of the heatwave, sources have told the BBC.

NHS England was alerted to six critical incidents on Thursday morning.

It comes amid reports the extreme heat has caused problems with IT systems, cancer equipment, lab testing and scanners.

Critical incidents are declared when a service is under extreme pressure that threatens a hospitals ability to deliver safe and effective care.

NHS trusts use it as a signal to the workforce and wider system that staff may need to be redeployed and patients sent to nearby hospitals.

Two the BBC has been reporting already are Portsmouth’s Queen Alexandra Hospital which declared a critical incident after a cooling system supporting "critical infrastructure" failed partly due to the pressures of the heatwave.

The Norfolk and Norwich NHS Trust has reported one too saying its cooling systems used to keep it scanners running had been affected by heat and humidity.

To put that in context, the NHS has got to the point in recent winters where more than 20 NHS trusts have declared critical incidents at points.

The latest provisional temperatures are in. As of 13:00 BST, parts of the UK have surpassed 34C.

Here's a closer look:

• Shoreham Airport - 34.7C
• Thorney Island, West Sussex - 34.5C
• Yeovilton, Somerset - 34.5C
• Larkhill, Wiltshire - 33.9C

Meanwhile, the temperature at Jersey Airport is continuing to rise, it has now reached 36C.

Barra Best
BBC News NI weather presenter

Davina Girvan is making sure her dog Chico stays cool in Cultra, County Down.

"We bring him down early in the morning with plenty of water, let him have his walk around," she says.

The Lhasa Apso is named after singer and former X-Factor contestant, Yousseph "Chico" Slimani.

Davina says "he goes in the wee stream to cool off and then we go back in the car which has a cool mat with gel along the back seat so that when he moves it activates the gel to keep him cool".

"Once he's panting or looking for shade that's when we leave," she adds.

Image source, Getty Images

Bethany Bell
Reporting from Leipzig, Germany

Image source, Getty Images

Meteorologist Oliver Reuter says the heatwave in Germany will "ultimately be be described as historic".

Speaking to German Press Agency DPA, he says this is not only because the previous German record for June "is likely to be significantly surpassed, but also because there have never before been peak temperatures of over 40C, or even 41C, across so many places on three consecutive days in Germany".

What's the impact been?

In Hamburg, a half marathon race due to take place on Sunday has been cancelled because of the heatwave.

The heat is also affecting animals. One zoo in the west of the country took its alpacas to a nearby lake for a swim to cool off.

Meanwhile in neighbouring Austria, temperatures could reach up to 40C in Vienna at the weekend.

Image source, Getty Images

We can now bring you a snapshot of the latest provisional temperatures - taken at 12:00 BST.

The village of Yeovilton in Somerset reached 33.2C, while Jersey Airport recorded 34C.

Other places have also hit temperatures above 30C:

• Shoreham Airport - 33C
• Thorney Island, West Sussex - 33C
• Bournemouth Airport - 32.5C
• Wiggonholt, West Sussex - 32.7C

As a reminder, today's highest temperatures are likely to be recorded at around 15:00 or 16:00.

Calum Watson
BBC Scotland

As Scotland prepares for what could be its hottest day of the year so far, one council is sending out its fleet of gritters to treat the roads.

Scottish Borders Council says that instead of salt, the lorries will be spreading a fine layer of sand to stop the road surface melting.

The authority's chief executive David Robertson said some parts of the region could see temperatures reach 31C.

"What we’re seeing is ambient road temperatures at the height of the heat up in the 40s - and that causes the tar on the road to melt.

"So if you see the gritters, it’s not the council being daft – it's us trying to protect the road surface."

South East Water says it acknowledges customers will be frustrated by a hosepipe ban that's been introduced in Kent.

Around 850,000 customers will be affected by the ban, which has been put in place "due to high temperatures and record demand for water".

The company's treatment works are all operating at 100% but are struggling to keep up with "demand at record levels", head of water resources Nick Price tells the BBC.

"Reservoir levels are healthy," he says, meaning there's no underlying shortage of water - just a shortage of processing capacity.

To give a sense of demand, Price explains the typical daily water usage in June is 580 megalitres, but "yesterday it was over 680 megalitres".

Price says he understands frustration over the ban when South East Water is still losing 100 million litres of water a day through leaks.

The Met Office has just issued a new yellow thunderstorm warning for Northern Ireland. It will come into effect from midnight on Friday, lasting until 10:00 BST.

There are already several weather warnings in place across parts of England, Scotland and Wales over the coming days - you can read more about those in our previous post.

The high temperatures are continuing into Thursday as some parts of the country experience their second day under a red heat warning.

Umbrellas and fans are among the techniques we've spotted being used to cope in the heat.

Image source, AFP via Getty Images

Image source, PA Media

Image source, BBC Weather Watchers/uWhoAndyR

Anna Lewis
BBC Wales

Image source, Getty Images

A man has died after going into the sea on a popular Welsh beach, police have confirmed.

Emergency services were called to Aberavon beach, Neath Port Talbot, on Wednesday afternoon, after a 50-year-old man required medical assistance.

South Wales Police said the coastguard attended and performed CPR before an air ambulance and paramedics arrived.

Despite their best efforts, the man from Cilfrew, Neath Port Talbot, died at the scene at about 16:50 BST.

His next of kin has been informed, the force said. The death is not being treated as suspicious.

Charlotte Cox and Olivia Fraser

Some school children in Guernsey are doing their learning in an underground bunker in a bid to beat the heat.

Temperatures on the island reached 33.8C (98.6F) on Tuesday.

La Houguette Primary School headteacher Claire Judd says some Year 3 children had begun to feel sick in the classroom on Wednesday, which was when their teacher remembered the bunker on their doorstep.

The island is scattered with hundreds of German fortifications built while it was occupied during World War Two.

The children have since been "nipping down" for short cool-off periods, says Judd, with a lesson also taking place in the unusual setting.

The school has also given pupils cool water footbaths to help them cool down during their lessons.

Judd says a Year 5 teacher had suggested the footbath idea and the children "just love it", with one saying it was the "best day in Year 5 ever".

• You can read more about how La Houguette Primary School is coping with the heat here

Image source, Met Office

Thursday

A red warning for extreme heat is in place in London, parts of southern England and southern Wales. An amber heat warning is in place for a wider area across south and central England and Wales.

A yellow warning for thunderstorms is in place in northern Scotland from 15:00 BST, while another is in place in south-west England, from 18:00.

Friday

A red heat warning covering London and parts of south-eastern England will be in effect until 21:00. A separate amber warning for extreme heat will be in place all day for south-east England, eastern England and parts of the Midlands.

There are also two yellow warning for thunderstorms. One covering the whole of Scotland until midnight and another covering large parts of northern and western England and Wales.

Saturday

An amber warning for extreme heat will be in place on Saturday until 21:00. It covers London, the south-east, and east of England.

Elizabeth Rizzini
Lead weather presenter

Image source, Met Office

The Met Office has issued another warning for thunderstorms for tonight and tomorrow morning until 10am affecting northern England, the Midlands, Wales and part of south-west England.

Many places will miss the worst but within the warning area there is the risk of frequent lightning and of sudden, gusty winds with 50 to 60mph possible, particularly in the south and west of the warning area.

Frequent lightning, hail and heavy rain (possibly 15-20mm in an hour) will be additional hazards.

There could be some surface water flooding, difficult travelling conditions and possible power cuts.

This is in addition to the yellow thunderstorm warning across Scotland valid all day tomorrow, and the two thunderstorm warnings in northern Scotland today and south-west England valid from 15:00 and 18:00 today respectively.

Image source, EPA/Shutterstock

A rare red warning for extreme heat means the hot weather will have a population-wide impact on health that could lead to serious illness and a danger to life, according to the Met Office.

Here are some practical considerations you can take:

Avoid train journeys: Train operators are warning people against non-essential travel, with a number of services already delayed or cancelled.

Take care driving: Ten people were hospitalised after being trapped in hot weather for hours following an accident on the M25 on Wednesday.

Check for school and workplace closures: Hundreds of schools have been closed - or partially closed - and some workplaces are advising staff to work from home if possible.

Carry water: Stay hydrated, and if possible avoid caffeine and alcohol before bed. Water fountains are available in some public places, including train stations.

Sleep with a fan: To help cool your bedroom down, place a fan in an open window at night, or put ice packs and wet towels in front of it to help cool air circulate.

Simon King
Lead weather presenter, BBC Weather

The Met Office has extended the red extreme warning into Friday for London and parts of south-eastern England.

It will be valid from 00:00 to 21:00 BST.

Temperatures are expected to remain in the low to mid thirties and with high humidity - it will continue to bring health impacts to the wider population along with transport disruption.

Image source, Met Office

Nick Triggle
Health correspondent

Some medical professionals are sharing their concerns about how the extreme heat is affecting the NHS.

Doctors are reporting increased pressure and difficult conditions in hospitals, says the Royal College of Physicians.

The college says there are numerous reports of older patients being brought in after collapsing because of dehydration. It adds its members are saying the extreme heat is causing machines and equipment to malfunction.

Some sites have reported problems with testing laboratories and cancer machines. And one doctor says they had been told to turn off all non-essential equipment, including lights and computers, because of IT problems.

A critical incident was declared at Portsmouth’s Queen Alexandra Hospitalafter a cooling system supporting "critical infrastructure" failed - partly due to the pressures of the heatwave.

And, as we've just reported, the Norfolk and Norwich NHS Trust says its MRI scanners have stopped working due to the heat.

Other college members say staff and patients were “really struggling” in over-crowded and over-heated buildings with few sites having air-conditioning to keep public areas cool. Conditions are described as “awful” by another doctor.

Nikki Fox
East of England health correspondent

Image source, Getty Images

Hundreds of patients in Norfolk have had hospital appointments cancelled after MRI scanners stopped working during the hot weather.

The Norfolk and Norwich University Hospitals NHS Foundation Trust has declared a critical incident, saying the cooling systems that keep its scanners running had been affected by the heat and humidity.

The units generate a significant amount of heat when in use, so they rely on cooling systems to keep them within safe operating temperatures.

The trust said it currently has "no working MRI scanners" across its Norwich sites, including those at the main hospital and its community diagnostic centre.

At least 254 outpatient appointments have already been cancelled. The trust said it is contacting affected patients directly and will rearrange appointments "as soon as our scanners are functioning once more".

• Read more: MRI scanners not working at Norfolk trust due to heat

Hugh Schofield
Paris correspondent

A three-year-old boy died of heat suffocation on Wednesday afternoon after getting stuck in the family car, French police report.

It happened in the northern Paris suburb of Saint-Gratien. The boy was supposed to be taking a nap inside the home, but woke up and - without his parents knowing - went to the car.

According to French news agency AFP, the car doors were unlocked from the outside, but inside the child-lock had been activated so he could not get out. The outside temperature would have been in the late 30Cs.

The boy’s distraught parents tried heart massage to reanimate him, but emergency workers declared him dead.

On Monday, two siblings aged two and four died in similar circumstances in the southern French town of Carpentras.

The Met Office has issued a new yellow warning for thunderstorms for parts of northern Scotland, in place from 15:00 to 23:59 today.

It says there could be "spells of rain and thunderstorms may lead to disruption in a few places".

It adds: "There is a small chance that homes and businesses could be flooded quickly, with damage to some buildings from floodwater, lightning strikes, hail or strong winds."

Image source, Met Office

Chris Fawkes
BBC Weather

I wouldn't normally be talking about temperature reaching the 30C mark at 10:00 BST in June, but then this is not a normal heatwave.

The mercury has just hit 30.4C at Shoreham, West Sussex.

We expect today's highest temperatures will be recorded much later - around 15:00 or 16:00.

Image source, Sussexspotter / BBC Weather Watchers