Parents must treat the threat to children from jumping in the river 'as seriously as drugs and knives'.

The warning comes from the leader of Richmond Borough Council, Gareth Roberts, following the tragic drowning of a 14-year-old in the Thames at Hampton.

At the same time a leading local head teacher has urged youngsters to stay away from the river despite the temptation to jump in and cool off in today's record temperatures, which could reach 40C.

Families have reacted with horror and sadness to the death yesterday afternoon, which has been linked to a group of youngsters jumping off a bridge into the water at Taggs Island.

Other riverside bridges at Teddington Lock and Hampton Court have been the centre of similar reckless activity during the current heatwave.

Youngsters have continued to take their lives into their hands despite repeated warnings from the Council, the RNLI and the Police.

Cllr Roberts, who represents Hampton, said: "The tragedy at Taggs Island underlines how dangerous the river can be.

"The Council and partners can only do so much but preventative measures, like fences at Teddington Bridge, have been torn down.

"Parents need to treat this as seriously as drugs and knives and warn their children."

Cllr Roberts told Sky News: "This is an absolute shock.

"We have always had the warnings but we have always expected something like this might happen.

"We put out warning after warning to try to discourage people from jumping off bridges.

"We have a big problem in the borough – and it is not just limited to Richmond of course – with children and young people finding bridges, seeing the river and thinking it is perfectly safe.

'Unfortunately, they will jump in and tragedies like this will happen."

Cllr Roberts added: "We are incredibly saddened to hear about the tragic drowning of a young boy in the Thames in Hampton yesterday. Our thoughts are with his parents, family and friends.

"I also want to give my huge thanks to the emergency services who launched a rescue operation yesterday. Unfortunately that has now become a recovery operation and that operation is continuing today."

He issued a warning, saying: "The Thames is a dangerous river. It is has a strong current, with houseboats in many areas, as well as moving river traffic, that pose dangers to anyone swimming in the river.

!It is full of debris including sharp metal, shopping trollies and other items that can cause serious risk to life if hit. There is also a risk of cold water shock, as parts of the Thames remain very cool even in this hot weather."

Cllr Roberts said: "For many years, this Council, along with our neighbouring local authorities and partners including the RNLI, Port of London Authority, Environment Agency and Met Police have been warning residents of the dangers of swimming in the Thames. 

"Despite these stark warnings of the dangers, swimming in dangerous parts of the river has remained a problem in Richmond upon Thames, particularly at Teddington Lock.

"Here we have put in place mitigations, including Heras fencing and cactus spikes, to deter people from jumping into the river off the bridge. Despite our efforts, these are being removed and ripped off to allow access to the parapets. Unfortunately, it is usually young people and children who are gathering, jumping and swimming in these areas. 

"Richmond upon Thames has over 20 miles of Thames riverbank and 16 bridges. The river is a commercial river - we cannot put up barriers to stop swimming in all areas, and the Council and the emergency services cannot be in all places at all times to disperse gatherings and keep swimmers out of the water. 

"There are many safe ways to enjoy the river, such as through local water sports providers, rowing clubs or boating companies. All have stringent health and safety in place, including trained guides and coaches.

"It is heart-breaking that we have reached the point where a young boy has lost his life and a family have lost their son. If there is one thing to come out of this tragedy, I hope it is that people will finally realise the true dangers of this river and do what they can to make sure this never happens again."

A number of residents have complained that the fact that the outdoor pool at Pools on the Park in Richmond is not open to the general public means youngsters are more likely to cool off in the river.

The head teacher at Twickenham School, Assal Ruse, urged caution, saying: "Please do not go in the river. To all young people, in particular, we urge you to be the person in your group of friends who says no and reminds others about the dangers."

This morning the Metropolitan Police said a search has resumed this morning. A spokesman said: "Officers and divers from the Police Marine Unit are on scene.

"We are not currently releasing the name of the missing teenager."