While extreme weather events like heatwaves occur naturally, "research shows that with climate change they are likely to become more common, perhaps occurring as regularly as every other year, external", the Met Office says.

It conducted a study last year that found that the UK was now 30 times more likely to experience heatwaves compared to the year 1750, because of "the higher concentration of carbon dioxide (a greenhouse gas) in the atmosphere".

Records going back to the late 19th Century show that the average temperature of the Earth's surface has increased by about one degree since industrialisation.

A climatology institute in Potsdam, Germany, says Europe's five hottest summers since 1500 have all been in the 21st Century.

Scientists are concerned that rapid warming linked to use of fossil fuels has serious implications for the stability of the planet's climate.

Rescue dog Casey is playing it cool while she waits to find her forever home.

Forecasters are expecting temperatures in southern England to reach 39C on Thursday. The current record for the UK was 38.5C in Faversham, Kent, in 2003.

BBC News has mapped the hottest temperatures on record around the UK.

Here are some people who might not be quite so excited by the prospect of a scorching day...

Thousands are without water in Bristol after a main burst on Royate Hill..

Bottled water will be handed to vulnerable people and bowsers are being sent out.

Sharna Smith, from Bristol Water, said it was too early to predict when the main would be repaired. "We are aiming reroute the supply around the damaged area. But our priority is to get water to people," she said.

Properties in Speedwell, Eastville, Fishponds, Lockleaze, Horfield, St George and Stapleton are affected.

There is a lot of talk from the Met Office about how hot it is going to be (in short, very).

If like me you have ever wondered "how do they know that", watch this video from BBC Weather's Sarah Keith-Lucas.

If you haven't, watch it anyway, it may come in handy for a pub quiz one day.

Nick Hyde hit the beach early in Northumberland to get a run done. Nick we salute you!

It's not just the heat that is going to be burning down on people today.

BBC reporters are flocking to hotspots across the country, be sure to say hello and share your staying cool tips with them.

You can also contact us directly via email at england@bbc.co.uk or on Twitter at @BBCEngland, external.

Pictures of dogs particularly welcome.

Image source, Getty Images

While southern and eastern England are braced for the biggest scorching, the rest of the UK should also be preparing for the heat according to the Met Office.

Temperatures of up to 39C (102.2F) are being forecast in southern and eastern England, with the Met Office saying there is a 60% chance the current record of 38.5C (101.3F), which was set in August 2003, will be broken.

Image source, Getty Images

But it is also expected to be a tad warm elsewhere, with parts of Scotland expected to see temperatures close to 30C and areas of Wales actually hitting 30C.

Anyone looking to avoid the heat may want to head to Northern Ireland where a weather front should keep the heat at a more balmy 22C.

Is the sunshine scuppering your commute?

It might be if you're taking the train today - temperatures on the tracks could top 50C in direct sunlight, which could cause them to buckle.

Network Rail says train speeds will have to be reduced on the West Coast main line, Chiltern line and other services.

It's not just babies struggling in the heat, spare a thought for our furry friends.

BBC Newsround has some advice on how to keep your pets as chilled out as this cat.

BBC Weather Watchers

Our BBC Weather Watchers are already out on a day that could see record-breaking temperatures in the UK.

Jeff has posted this scene saying it's already 21C (70F) in Sandon Staffordshire.

Image source, Jeff

This is Peter Steggles's view in Longnor, Shropshire.

Image source, Peter Steggles

And this sunny scene was taken by Janiejane13 in Hereford.

Image source, Janiejane13

Windows open? Fan on?

One leg in the covers, one leg out?

If you're struggling to get some decent shut eye in this weather, fear not. Tonight is going to be better with these handy tips to help you drift off - including chilling your socks in the fridge.

Yes, really. Cooling your feet is the key to lowering your temperature. Who knew?

Image source, Getty Images

Emma Kasprzak
BBC Online

The UK heatwave is trending on Google with lots of parents turning to the search engine to find out how to keep their little ones safe in the heat.

This video from BBC Family has some tips from baby Leo for keeping cool in hot weather.

Pro tip: Paddling pools make great foot spas once the kids are in bed.

The Met Office said there was a 70% chance of the current record of 38.5C (101.3F) from August 2003 being broken.

Network Rail warned of disruption in areas where tracks were at risk of buckling - with many rail firms advising passengers not to travel.

Image source, Image copyrightDANNY LAWSON/PA WIRE

With temperatures forecast to reach up to an all-time high of 39C in southern and eastern England on Thursday, we'll be bringing you the latest news, information and pictures from across the UK.