A 12-year-old was sprayed in the face with an unknown substance before her phone was stolen.

She was approached in the alleyway alongside Wandsworth Common and Routh Road, Wandsworth, at about 4.20pm on Friday, June 12.

The man who demanded her phone was a light-skinned black man riding a dark bike, about 5ft 4in with black curly hair past his ears. He was wearing a white top with blue jeans and had a London accent.

He then sprayed her with the unknown substance causing her to drop the phone, which he then took and cycled towards Trinity Road.

The second spraying took place on the same day between 4.10pm and 4.30pm in Gayville Road, Wandsworth. Three 16-year-old boys were approached by a light skinned black boy, about 13 years old.

He sprayed one of the boys in the face with an unknown substance and cycled towards Thurleigh Road, although no items were taken.

He was riding a black and red bike and was 5ft 5in with black curly hair and of a slim build. He was wearing a black hooded top with tracksuit bottoms and had a small black and white bag with Adidas on the front.

Detective Constable Catherine Peatfield CID said: "We are linking both offences and as a result have increased the number of officers patrolling the area. Even though we have two separate suspect descriptions, there is a strong possibility that the offender could be the same person.

"It is not yet clear what the liquid was, what we do know is that on both occasions it was sprayed from a can.

"Fortunately none of the victims suffered any serious of long-lasting injuries."

No arrests have been made.

Anyone with information is asked to call Detective Constable Peatfield on 020 3276 2586.