Hazel Shearing
Education correspondent

We've now counted 837 schools in England which have fully or partially closed, or which are offering parents the option to pick their children up early.

Most schools are open, but that doesn't mean all their pupils are present. Some trusts have reported a big impact on attendance.

Education Secretary Bridget Phillipson is warning that pupils in England shouldn't be missing school when they can go in because they'll miss out on learning.

"I know hot weather can be a struggle. But my message to families is simple: if your child’s school is open, you should keep sending them into school," she says.

“Every day of absence and lesson missed has a cost – and that cost falls hardest on our most disadvantaged pupils and working class communities.”

She adds that relaxed uniform rules are among the things schools are doing to keep children cool, and any family with concerns about medical needs should talk to their school.

Temperatures in England reached 33.9C at 13:00 this afternoon, recorded at Thorney Island in West Sussex.

Cavendish in Suffolk was 33.6C at the same time, while both Wisley in Surrey and Shoreham in West Sussex reached 33.4C. A maximum of 39C is not out of the question for southern England on Wednesday.

It was 30.3C in Cardiff, Wales. In Scotland, the 13:00 temperature was recorded as 24.2C in Charterhall. In Northern Ireland, it reached 23.4C at Castlederg.

Image source, PA Media

Letters and parcels will continue to be delivered as normal through the heatwave, Royal Mail says.

But the company says measures are in place to help manage the severe heat for postal workers.

It says local teams will review their plans and "adjust working arrangements where needed" to avoid over-burdening staff during the hottest parts of the day.

Manish Pandey
Live reporter

Image source, EPA/Shutterstock

Temperatures have continued to rise throughout the day, with highs of 37 or 38C expected to break the record for June later.

The Met Office's red warning for extreme heat is in effect and has been extended to 23:59 BST on Thursday.

The East Midlands, East of England, London & South East England, South West England, Wales and the West Midlands are all included - read more on what an extreme heat warning means for you.

High humidity will make it feel particularly hot when combined with the strong sunshine, says our forecaster.

The heat has caused significant disruption, with over 1,000 schools fully or partially closed in England and Wales.

Transport has also been hit, with rail operators altering their services and National Rail warning passengers not to travel unless absolutely necessary.

Meanwhile, in Europe the heatwave continues, with half of France remaining under a red heat alert.

Peter Gillibrand
BBC Newsbeat

Image source, Supplied

Bricklayer Elijah knows a thing or two about working in the elements.

He spends every working day outside and tells BBC Newsbeat that getting through bad weather, be it cold or heat, is just “part of the job”.

“I tried to keep the complaining to a minimum because about ten months of the year, you're in rain and the cold,” he says.

He admits the heat has been “a lot to deal with”, adding: “We've been starting early, at like 06:30 or 07:00, and trying to get out by midday because by [that time], there's not much you can really do at that point.”

He's laying on water and ice lollies to help keep his employees cool but says “I tell people if they don't want to come in because of the heat don't bother, don't risk it".

Esyllt Carr
Business reporter, BBC News

Image source, Getty Images

Greggs has temporarily closed 11 stores today and tomorrow for the safety of staff and customers.

Staff at one London branch say employees have been moved from one shuttered store to others around capital, telling the BBC: “It's very hot. We have industrial ovens but no proper air conditioning in stores.”

The stores affected are: Aldridge, Wolverhampton, Luton, Gosport, Trowbridge, Barnet, Marlborough, Wantage, Dudley, Northampton and Leicester Square, London.

Jasmine Sandhar
BBC Newsbeat

Emery, 17 from Gloucester, is having a good afternoon.

The ice cream man is out with his dad and says customers are coming out on "almost every street" during their rounds, with the heat being “good for money and for the business".

But there are costs too - everything in the van is plugged in overnight to keep it cool for the next day.

During scorching days, they make sure to keep the windows open and have a vent in place to stop their 99s and lollies becoming puddles.

The family also run a burger van but that’s taking a back seat this week. Emery says: "You have the air fryers coming up for 120 degrees. My co-worker’s shirt was drenched in sweat."

Over on BBC Radio 5 Live, chef Luke in Colchester says the heat is "an occupational hazard" and they "have to get on with it" adding: "We have hot lamps that are running from midday to midnight.

"Ovens running at 200 degrees all day. Gas ring burners with pans on. It’s like working next to a radiator, in a radiated kitchen."

Sue, a nurse from Blandford, just finished a night shift and has no idea how she'll get to sleep.

She says there is no air conditioning in her hospital building and they are handing out drinks by each bed to keep everyone hydrated.

Andrew, a head teacher of a primary school in Tottenham, says it's hard balancing the risk of having children in schools and the risks of sending them home.

He adds that buildings at the school "aren’t designed to handle this weather" and they don't have much shade in playgrounds "to keep people safe".

Matt McGrath
Environment correspondent

There's been a rare summer warning from Britain's electricity grid operator as the heatwave puts more pressure on our power system.

The National Energy System Operator (NESO) has put out what's called an "Electricity Margin Notice" for this evening, which means it is asking those generating electricity to make extra capacity available.

Such notices are normally seen in the winter, when our demand for electricity ramps up as we warm our homes on those cold, dark evenings.

Seeing one during a heatwave is unusual.

The pressure comes from both the supply and demand sides during the hot weather.

The warm, still conditions tend to suppress wind output, while high temperatures reduce the efficiency of solar panels and conventional power plants.

At the same time, demand can rise due to the extra electricity needed for air conditioning.

NESO stresses that this does not mean that blackouts are likely, or that there is too little power to keep the lights on, and it will review the situation through the day.

Sarah Keith-Lucas
BBC Weather

Meteorologists here in the Met Office operations centre are very busy analysing huge quantities of weather data and observing closely how conditions are developing across the UK.

The forecasters here tell me the forecast is going as expected today, with temperatures rising quickly and humidity staying very high.

The next weather hazard they are looking into is the potential for some severe thunderstorms with large hail and the possibly onset of gale force gusts of wind for south-west England during Thursday night - a yellow warning has just been issued.

Image source, Met Office

The Met Office has issued a yellow warning for thunderstorms in south-west England on Thursday.

It will come into force between 18:00 and 23:59 BST, covering all of Cornwall and much of Devon.

Image source, House of Commons

Over in the House of Commons, the heatwave has just come up during this week's Prime Minister's Questions.

Responding to Liberal Democrat leader Ed Davey, Keir Starmer says the changing climate is "one of the most significant challenges of our time".

The prime minister says it used to be "common ground" that climate change was a "generational challenge", but that it is a "shame that in order to chase Reform votes" the Conservatives have "changed their minds".

"I will always maintain that we must be global leaders on climate change and we always will be," Starmer adds.

Hazel Shearing
Education correspondent

There's no set temperature at which schools are told they need to close in a heatwave - that decision is made on a case-by-case basis.

I asked Tim Warneford, whose consultancy helps schools obtain funding for their buildings, whether he expected quite so many to do so.

"I think it was a ticking time bomb," he replies, since England's ageing school estate was "not built to withstand the temperatures that we are now facing and are likely to face into the future".

"New buildings, we hope, will be designed sufficiently well that will reduce that risk, but the overwhelming number of our stock is going to require retrofit - and therefore that's going to require a certain amount of money," he adds.

A big problem is that many schools built in the 1950s and 1960s have "almost floor-to-ceiling windows" which trap in heat and are challenging to ventilate.

He adds that only schools built in the past decade or so are likely to have been designed with air conditioning units - and warns that some of those may not even be up and running because they're expensive to maintain.

Chris Fawkes
BBC Weather

Last night was the warmest on record for some UK sites, including at Brize Norton (Oxfordshire) where temperatures only fell to 22.3C - what is known as a tropical night.

From this warm and humid start, temperatures are rocketing upwards. Even before midday we've reached 31.6C at Thorney Island (Hants).

The June record of 35.6C is going to get smashed later this afternoon, with highs of 37 or 38C likely around 15:00 BST in southern England.

This would put us well inside the top ten hottest days ever recorded in the UK.

Global heating is to blame for such unprecedented heatwaves. You may remember that last month the May record was pulverised by well over 2C - it's clear that our climate has changed.

Matt McGrath
Environment correspondent

Image source, Justin Tallis/AFP/Getty Images

A meeting in London on how to adapt to extreme heat has fallen victim to the very thing it was seeking to tackle.

The session, scheduled at the London School of Economics during London Climate Action Week, was due to explore how countries and cities are responding to rising temperatures around the world.

But organisers cancelled the event after the Met Office issued a red extreme heat warning.

Chris Anderson from Practical Action, who was due to take part in the event, says: “We're fully in favour of the decision, for the wellbeing of attendees and panellists.

“But it shows that extreme weather is becoming unpredictable and moving faster than people can adapt, even in the richest countries.”

Beth Rose
Disability affairs reporter

Image source, Getty Images

As temperatures rise, the effectiveness of medications can change.

The Medicines and Healthcare products Regulatory Agency (MHRA) says heat damage can break down active ingredients in medicine.

That can stop or alter how much the body absorbs when it comes to tablets, inhalers, hormone patches, insulin, blood glucose monitors and EpiPens.

Dr Alison Cave, MHRA’s chief safety officer, says some medicines can also make you more likely to "burn in the sun, feel dizzy, or get dehydrated", especially if you’re taking diuretics or have a condition like asthma, heart disease or diabetes.

She says most medicines need to be stored at temperatures below 25C - but cars, trains and even bags and pockets could get warm enough to cause problems and keeping them in a cool bag could be useful.

She adds: "If your medicine has changed colour, developed an unusual smell, changed texture, or looks different in any way, this could signal heat damage. Ask your pharmacist for advice."

Does the warm weather have an impact on the economy?published at 11:53 BST

11:53 BST

Dharshini David
Deputy economics editor

As some trains grind to a halt - is the economy in danger of doing the same?

The answer is no - after all, whatever the disruption, most of us are still working.

And while events are being cancelled, that activity may simply be displaced if they are rescheduled. Equally, other forms of spending - on fans, ice cream and extra childcare if you’re dealing with school closures - may rise.

So, however tempting, it’s impossible to put a reliable number on this.

In the grand scheme of things, short-lived weather events don’t tend to shift the dial much in terms of overall GDP. But economic activity may be a bit sluggish overall for a few days as the temperature rises.

Miho Tanaka
Senior climate journalist

Image source, Gwyndaf Hughes/BBC

The Engine Room in Tottenham Hale normally serves as a community centre for local residents to get together for walks, and arts and crafts.

But this week it is serving another purpose - a “cool space”.

One of dozens designated across the capital offering respite from heat for residents, mostly elderly people.

The spaces have air conditioning systems, seating, free drinking water and bathrooms.

Frederica Roberts, tells the BBC the centre offers them ‘”absolute tranquillity” away from the “hustle and bustle”.

Her friend, Marion Wilson, jokes that spending time at the centre offers them “a relief especially with half of us that are menopausal. If you have that and you have heat, it's not good to be around us”.

Rory Bibb
Reporting from London

Johnny is a construction worker on a site in London where temperatures are already soaring.

He says: "It’s horrible. You’re outside all day and there’s no let up. We might be going home early, but there’s work to be done."

"We're all hot, and we're all in the same boat. No one's dropped down, touch wood,” he adds.

UK employers are issued health and safety advice on how to protect outdoor workers in these sorts of conditions.

But there is no legal maximum temperature at which work has to stop as there is elsewhere, meaning it's business as usual for people in industries like construction and farming.