An armed robber escaped from a secure psychiatric hospital in Tooting before robbing a shop at knife-point, a jury has heard.

John Slavin, 44, was eight months into a sentence at Springfield Hospital for robbing a Gloucester Road bookshop when he vanished during a cigarette break, the court heard.

His mental illness meant he was not fit to make a plea, judge Stephen Robbins told jurors at Southwark Crown Court on Monday.

Mr Slavin allegedly escaped through a fence with another man when he and 11 other prisoners had a cigarette break in March 2008.

Within 24 hours he armed himself with a knife and revisited the bookshop.

Mr Slavin is accused of four counts of robbery, possessing an offensive weapon and escaping from lawful custody.

The trial continues.