A security guard delivering money suffered a broken arm when he was attacked and robbed at a Bristol petrol station.

The crime happened at about 10.15pm on Thursday at the Texaco garage in Northumbria Drive, Henleaze.

Robbers escaped with a cash box containing "a substantial amount of money", said police.

Avon and Somerset police spokesman Simon Whitby said: "It is not thought any weapons were used.

"The attacker, who was wearing a black balaclava, ran from the scene with another man and met a third man on the corner of Devonshire Road.

"They were seen getting into a new silver car, possible an Astra or a Golf, and drove off towards Coldharbour Road.

"It's believed there were four or five men in the car, one of them of mixed race."

As well as witnesses to that incident, police want to hear from anyone who may have seen the car a little earlier near the Somerfield service station in Falcondale Road.

It was parked between Westfield Road and Falcondale Road, and three men were seen to be acting suspiciously.

Police also want to speak to anyone who saw the silver car in Worrall Road at around 11.05pm.

Witnesses report seeing two youths get out of the car carrying a package and walking up the drives to two houses. The empty cash box from the robbery was later found dumped in a bush in a front garden.

Anyone with information should call Bristol CID on 0845 4567000 or Crimestoppers, anonymously, on 0800 555111.