A doctor has warned south London residents to remain vigilant as temperatures are expected soar up to 30C over the bank holiday weekend.

With the capital set to sizzle medical experts have offered advice to people so they avoid becoming ill.

Dr James Marsh, joint medical director at Epsom and St Helier hospitals said: “As always, our staff will be on-hand to care for people who need us, but we all know that prevention is always better than the cure.

“I would urge everyone to enjoy the heat and sun safely, by making sure that you stay cool and hydrated. And don't forget the sunscreen!

“Those with heart, respiratory and other serious health conditions are more at risk, and the heat can sometime make these conditions worse. The elderly, babies, and young children are also especially at risk.”

Doctor Marsh’s tips for keeping cool are:

· Keep windows closed when the room is cooler than it is outside

· Open windows at night when the temperature outside has dropped

· Reduce heat from sunlight coming through the windows

· Have plenty of cold drinks, avoid excess alcohol and caffeine

· Have cool showers or baths, put a loose, cotton, damp cloth or scarf on the back of the neck, and spray or splash your face with cold water frequently to help keep your body cool.

Danger symptoms to watch out for in hot weather include:

· Feeling faint and dizzy

· Feeling short of breath

· Vomiting

· Increased confusion.

If you feel affected by these symptoms try to cool down as quickly as possible. Remember to avoid paracetamol, which can make you worse, and seek further advice from NHS 111 or a doctor if symptoms persist.

If someone you know who is likely to be at risk during a heatwave, give them the support they need. Elderly people should be visited daily to see whether they are OK.

Call 999 immediately if a person has collapsed.