An elderly cyclist has been taken to hospital after suffering a heart attack in Bridge Road, Chessington.
South East Coast Ambulance said the man, thought to be in his 80s, had stopped breathing, and that a member of the public performed CPR before paramedics arrived.
The man was taken to Epsom Hospital in a serious condition.
London Ambulance said he had suffered a cardiac arrest.
Kingston police said the man was found collapsed at the side of the road near the junction with Hook Road.
A spokesman said: "It is not believed that any vehicle was involved."
The London air ambulance attended the incident after a 999 call at about 2.10pm.
Bridge Road was closed both ways but has reopened.
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