A man armed with a knife mugged one 12-year-old and tried to rob a second in Epsom.

The two incidents occurred within 10 minutes of each other as the two victims walked home from school last Monday afternoon.

Detective Constable Sarah McCabe said the first 12-year-old was walking along Cheam Road about 3.20pm when he saw a man standing at a bus stop near Banstead Road.

The suspect approached the victim and opened his bag revealing a knife and asked the 12-year-old if he had any valuables.

The victim tried to walk away and was threatened with the knife before the suspect walked away along Cheam Road.

Ten minutes later, another 12-year-old was walking along Cheam Road towards St Paul's Church with his brother and two friends when the same man approached them from behind.

He took the victim's mobile phone and pulled a knife out of his bag and threatened the 12-year-old with it.

D Con McCabe said police are looking for a black man, aged 18, 6ft tall, of medium build, with black hair in corn row style, wearing a dark-coloured jacket and carrying a dark-coloured shoulder bag. He spoke with a deep voice.

"We clearly need to find the person responsible for these robberies," D Con McCabe said.

"I am keen to speak to anyone who was in the area at the time of the offence and thinks they may have seen something or who recognises the description of the suspect."

Anyone with information should call Epsom CID on 0845 125 2222 or Crimestoppers anonymously on 0800 555 111.