DETECTIVES are asking people to watch out for orange-stained pound notes, after a shopkeeper was robbed in daylight.

The assault happened on Friday as the trader walked with his shop takings to the post office, in Bishop Auckland.

He had reached the post office in Tenters Street, when a youth tried to grab the security satchel which contained a substantial amount of money.

There was a tussle, but the youth grabbed the bag and fled over a footbridge to Edgar Grove.

Police say the theft will have activated an orange dye which will have stained the notes in the bag and possibly the mugger.

Detective Inspector Billy Hugill said: "The security bag should have released an orange dye on to the contents.

"Further more, once the bag is opened, an orange smoke will pour out and the orange dye will stick to whatever it comes into contact with - clothing or money.

"We are looking for witnesses to the incident, or people who have come into contact with orange-stained money.

"It could be that someone is walking round in an orange-stained jacket."

The youth is described as in his late teens or early 20s, slim, with dark clothing and a baseball cap.

If anyone can help detectives, contact them on (01388) 603566.