Thieves have made off with around £500,000 (US$0.89m) worth of chocolate after stealing seven lorries from a distribution centre in Lancashire.

Four of the lorries, which each contained about £80,000 worth of Cadbury's chocolate, have since been found empty, but the other three are still missing, reported BBC News Online.

The robbers tied up two security guards at the Great Bear Distribution Centre in Skelmersdale at 0130 BST and drove them to a field five miles away where they were held until 0600 BST. Lancashire police say the guards were unhurt, but shaken up.