* RNLI warning to teens not to jump into the River Thames.

* Stay off the trains unless journeys absolutely necessary.

* Government says headteachers have final say if schools remain open.

* Don't use disposable barbecues in parks.

* Risk of road surfaces melting.

* Household rubbish collections start at 5.30am to protect workers.

* Even hotter on Tuesday.

Richmond is set to suffer record temperatures today, pushing towards 40c and 100F, making it hotter than parts of the Sahara and the Caribbean.

Swimming in the River Thames is seen as one way of staying cool with the result teens and families have cooled off by taking a dip over the weekend.

However, the RNLI lifeboat station has warned people against jumping into the Thames, particularly in Teddington, where youngsters often congregate to leap off the bridge.

It is understood that the borough's schools will remain open over the next two days, however there are concerns that large numbers are planning to go into the river later today.

At the weekend the crew and police were called to the Lock area after a 13-year-old was seen to jump in the water but not resurface. Eventually, police on the scene were able to confirm he had made it to the shore safely.

Richmond Council has warned residents: "Don't put yourself and others in danger by jumping into the Thames to cool down."

Lifeboat Operations Manager at RNLI Teddington, Matt Allchurch, said: "When the weather is warm like it is at the moment there is a temptation to go into the river and we see people jumping off the footbridge

"It's important to know that you don't really know what you are jumping into when you jump from the footbridge.

"There could be all sorts of obstructions under the water, there could be boats passing under just as you jump or other swimmers below you.

"The other danger is cold water shock where the body takes an involuntary inward breath when you jump into cold water and that can result in 2 litres of water in your lungs which is instant drowning.

"If you do survive that, then the secondary measure of cold water shock is the loss of the ability to move your arms and legs because all of the blood from limbs goes into your core to protect your core.

"So we have lost people in the last few years, young people who are good swimmers, trying to swim across the Thames. Even in this warm weather we are having at the moment the Thames is really quite cold.

"If you are going to use the river, stay close to the edge in shallow water."

South Western Railway issued a travel warning, saying: "Following the Met Office extreme heat warning, customers should only travel if absolutely necessary on Monday and Tuesday.

"There will be an amended service & reduced speeds, with changes likely at short notice."

The Royal Parks is worried about the impact of fires on the landscape and wildlife. It said: "Cumulatively fire can do great damage to grassland habitats as well as ancient trees and other habitats. These habitats are of great value, and the fires also kill any wildlife trapped in the blaze."

It has found evidence of lizards, grass snakes, toads, frogs, newts and stag beetles killed in fires in Richmond, Bushy and the other Royal Parks.

Richmond Borough Council said: "The best thing to do in the hot weather is stay out of the direct sun, especially between 11am and 3pm as UV rays are strongest during these hours.

"The Met Office has issued a Red weather warning for the UK with temperatures potentially reaching over 35C in some places from Sunday to Tuesday. This means you should take extra care to protect your health, and the health of those around you, during this hot period of weather."

It said that the top ways for keeping safe in the heat include:

*Look out for those who may struggle to keep themselves cool and hydrated. Older people, those with underlying conditions and those who live alone are particularly at risk

* Close curtains on rooms that face the sun to keep indoor spaces cooler and remember it may be cooler outdoors than indoors

* Use cool spaces if going outdoors, like parks with plenty of trees. Find out about more cool spaces available in London

* Drink plenty of fluids and avoid excess alcohol

* Never leave anyone in a closed, parked vehicle, especially infants, young children, vulnerable adults, or animals

* If you have to go outside in the heat, walk in the shade, apply sunscreen, and wear a wide-brimmed hat

* Avoid physical exertion during the hottest parts of the day

* Make sure you take water with you if you are travelling

* While swimming can be a nice way to cool off, do not be tempted to jump into the River Thames

If you feel dizzy, weak or have intense thirst and a headache, move to a cool place as soon as possible. Drink some water or diluted fruit juice to rehydrate. Avoid excess alcohol

If you have painful muscular spasms (particularly in the legs, arms, or abdomen), rest immediately in a cool place and drink electrolyte drinks. Most people should start to recover within 30 mins and if not, you should seek medical help. Call 111 if you feel unusual symptoms, or if symptoms persist

Call 999 if a person develops any signs of heatstroke as this is a medical emergency. Further information on heatstroke and heat-related illness are available on the NHS website -  https://www.nhs.uk/conditions/heat-exhaustion-heatstroke/