A 19-year-old man and a 21-year-old woman were walking along Southsea Esplanade when three youths struck.

The couple were asked for their money and when they refused one of the group revealed a large kitchen knife and searched the man.

After emptying the victim's pockets the group ran away in the direction of the Pyramids Centre – escaping with £20 cash, cash cards and a £300 Canon Power Shot camera.

The main offender, who wielded the knife and took the wallet and camera, was black, 5ft 7ins and about 17. He was of medium build and had a beard from his lower lip down to his chin.

PC Jo Clarke said: 'I would appeal to anyone who was in the area and saw or heard anything to contact me as soon as possible.'

The attack happened between 10pm and 10.20pm on Wednesday, May 14.

Anyone with any information should contact PC Clarke at Southsea Police Station on 0845 045 4545 or call Crimestoppers anonymously on 0800 555 111.