Brits are being urged to avoid public transport in the extreme heat, but if you have to travel then there are some easy tips to help you keep safe and cool.
The UK is braced to endure its hottest ever day on record, with a temperature of 41C likely today or tomorrow due to the effects of man-made climate change.
The Met Office has issued a red extreme heat warning for much of England, from London and the south-east up to York and Manchester, while Brits have been advised not to travel if necessary.
If you do have to make a journey today or tomorrow - whether that be in the currently sweltering UK or in a hot country abroad - you should be careful not to get overheated.
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Heatstroke and dehydration can be incredibly dangerous, and are made more likely when stuck on a cramped train or busy airport departure lounge.
If you are worried about the heat today and don't need to travel, then stay indoors, drink lots of water and follow these tips to keep cool.
If you do need to travel, then these bits of advice may be useful.
Water is your friend
Make sure you drink as much water as possible and regularly wash your hands and face to keep your body temperature low.
As tempting as it might be, drinking alcohol and coffee is a sure-fire way to make yourself dehydrated.
If possible, travel next to or on bodies of water rather than on trains, tubes and buses, as the breeze from the water's surface will be cooler and wetter.
Wear cotton
When the temperatures are soaring the best fabrics you can wear are ones that retain water, keeping you wet and cool.
Quick drying synthetic fabrics are terrible in the heat and will offer little protection against the sun.
Cotton holds in moisture well, can flow and hang off the body, and provides against protection against the sun's UV rays if woven tightly enough.
Cool clothing includes loose-fitting outfits, tunics, A-line dresses, cropped trousers and natural fabric shirts and blouses, left untucked.
Electrolytes are key
However much water you're drinking, if your body can't keep it in, then it's not much use.
Water should be coupled with electrolytes, which maintain the balance between fluids inside and outside your cells.
Consuming salty potato crisps, sugary sweets, coconut water or an electrolyte tablet are all good ways to keep your levels up.
Wear a hat
A fairly obvious tip but a key one.
Keep the direct sunshine off your head is the best way to stop yourself from overheating, particularly when shaded areas aren't accessible during trips.
Keep your neck cool
Splashing water on your wrists is a great way to keep your body's core temperature low.
Equally, draping a wet towel or a gel wrap around your neck will also keep your body temperature down.
Wearing a hat with a broad brim and neck protector is also a smart move.
Plan when you travel
However prepared you are, if you're heading out in the blazing early sun, then you may overheat.
If you can, travel early in the morning or later in the evening, when the sun hasn't had a chance to heat up the air too much.
The further away you are from when the sun is at its highest, the more shade there will be due to the sun's angle.
Check your accommodation
If you are off on a holiday or staying away from home for another reason, then make sure that your accommodation is suitable for the heat.
Hotels will be able to tell you if your room has air conditioning or a balcony to cool off in.
Having two windows on opposite sides of a room is a great asset, as they can both be opened to create a through flow.
Ask the hotel managers or whoever is running the accommodation whether they can provide you with a fan and light bedding.
It's always worth checking reviews before you travel to find out how others have dealt with the heat.
Choose your activities wisely
If you are on holiday during the heatwave and are keen to make the most of your trip, then be smart about how you do it.
Minimise the number of journeys you're making each day by clustering activities in certain areas, and avoid planning those outside without any shade for the height of the day.
