People are being urged to take extra care in the sun as temperatures are set to soar to 32 degrees.
The London Ambulance Service is advising people to keep as cool as possible by wearing a hat, using sun screen and drinking plenty of water.
Staff in the control room answered 5,472 emergency calls yesterday (Wednesday, July 16) compared to the 4,921 on the previous Wednesday.
Anyone with minor conditions can call NHS 111 or visit a minor injuries unit, NHS walk-in centre or pharmacists.
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