A mugger who armed himself with a brick was fighting for life in hospital today after his would-be victim knocked him to the pavement.

Police said the youth threatened a passer-by with the brick near the Clock Tower, Brighton, just after midnight last night.

The victim lashed out to defend himself and punched his assailant in the face, sending him crashing to the ground.

The youth suffered serious head injuries and was admitted to intensive care at the Royal Sussex County Hospital, Brighton.

Police were today trying to trace the other man.

A spokesman said: "We have spoken to a number of witnesses but we would like anyone else who may have seen the incident to come forward."

The spokesman said it was not clear whether the man would face charges, adding: "It would be a question of whether reasonable force was used."

Anyone with information should call the police on 0845 6070999.