Firefighters hosed down a teenage cyclist after he was sprayed in the face with an unknown substance near Kensington Palace.

Emergency services rushed to the scene near the Duke and Duchess of Cambridge's home in Kensington Gardens shortly after 10am on Tuesday.

The incident involved an “unknown substance” and a 17-year-old boy was taken to hospital, police said.

Photographs show police officers and firefighters wearing blue gloves while the shirtless teenager is doused in water. His discarded bicycle lies on the grass nearby.

A Met Police spokesman said: “We were called at 10.09am on Tuesday to reports of a person being sprayed with an unknown substance in The Broadway, Broadwalk, Kensington Gardens.

“Officers, the London Ambulance Service and London Fire Brigade attended the scene.

“A 17-year-old boy was taken to hospital as a precaution.

“No arrests have been made. Enquiries continue.”

A London Fire Brigade spokeswoman said that all enquiries were being referred to The Met.

The incident comes amid a shocking spate of acid attacks in London in recent weeks with the number of crimes soaring.

The Standard carried out an investigation last month which showed just how east it is to buy substances on London's streets.