With the hottest day of the year recorded this week, London Ambulance Service and London Fire Brigade have reminded sunseekers to take extra care in the hot weather.
Temperatures soared to 33C this week, and LAS attended 300 more category A calls than average on just one day.
With temperatures cooler but still peaking at about 25C this weekend, the city's emergency services have issued advice and guidance.
The LAS has said hot weather is causing an increase in calls to those feeling dizzy or sick in the capital.
Medical director Dr Fenella Wrigley said: “We see an increase in calls because people forget to stay hydrated and the heat can exacerbate heart and breathing conditions.
“Older people, the very young and people with pre-existing conditions are more at risk so please check on friends, family members and neighbours who are vulnerable.
“We urge everyone out enjoying the sunshine to drink plenty of water, stay in the shade to keep cool, cover up, carry any essential medication with them and drink alcohol in moderation.”
London's firefighters have also warned barbecue chefs to take care while flipping burgers to prevent fires.
Last year, the brigade was called out to 61 fires, up from the previous summer.
Head of community safety Chris O'Connor said: "All too often barbecues are left unattended or placed too close to flammable items like sheds, trees or fences.
"Even small disposable barbecues can cause considerable damage if you don’t keep a close eye on them.
"It's really important to make sure they're completely out once you've finished with them.
"It seems crazy that we need to tell people not to use barbecues on balconies or indoors, but we clearly do.
"Barbecue fires can spread quickly and could not only damage your home, but could cause serious injuries or worse."
Al fresco chefs should keep barbecues away from plants, sheds and fences, ensure they are level and will not tip over and drink alcohol in moderation if they are in charge of the lit grill.
The LFB advises keeping a bucket of sand or a hose nearby in case the flames get too high.
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