The assault happened at around 2.50am, in The Base Nightclub, formerly The Subway, in the Cowgate.

The 21-year-old victim was on the dance floor when he was approached by the suspect, who was wearing distinctive jewellery.

He punched the victim in the head and he fell down some steps, hitting his head off the floor and suffering a fractured skull. The suspect immediately ran out of the club.

He is described as mixed race, 30 to 35 years, 5ft 8ins tall, medium build, and wearing a white jacket, white peaked cap, blue jeans and white trainers.

He is also described as wearing a thick gold chain and large crucifix around his neck along with other items of gold jewellery.

A police spokesman said: 'The victim suffered serious injury as a result of this assault, and had to be taken to Edinburgh Royal Infirmary for treatment.

'We are sure there would have been a number of witnesses to the assault, and we are keen to speak to anyone who was in the nightclub at the time the assault took place.

'The suspect was wearing distinctive jewellery, and we are hoping this will jog people's memories.

'Anyone who witnessed the assault, or who recognises the description of the suspect, should contact police.'

Anyone with information can contact Lothian and Borders Police on 0131 311 3131, or Crimestoppers in confidence and complete anonymity on 0800 555 111.