Cadbury today recalled thousands of chocolate bars because they lack nut allergy labelling.

Dairy Milk Double Choc 250g promotional packs bearing the phrase "win a prize and a half" are affected.

Cadbury is investigating how the printing error happened, which led to the "may contain traces of nuts" message being left off the label.

It is warning nut allergy sufferers not to eat the recalled bars but to get in touch for a refund. The chocolate is safe to eat for people who do not suffer nut allergies, Cadbury said.

No other Cadbury Dairy Milk products or "prize and a half" promotional packs are affected.

"Cadbury wants all consumers to be able to enjoy our products and would therefore like to apologise to any consumers inconvenienced," the firm said in a statement. The firm has not received any customer complaints about the labelling problem, a spokesman said.