Burger giant McDonald’s apologised today after being prosecuted for serving up a meal containing a metal bolt.

The chain was fined #13,500 by magistrates in Dudley, West Midlands, after a customer bit into a sausage and egg McMuffin containing the bolt.

A spokesman for McDonald’s, which pleaded guilty to producing food not of the substance demanded, stressed that food safety was a top priority at all its restaurants.

"This was an isolated incident that may have been connected with the servicing of the restaurant grills a few days before the complaint," the spokesman said. "We apologise for the incident and can reassure customers that correct procedures have been reiterated across the business."

Dudley Council brought the prosecution against McDonald’s following the safety breach at the Merry Hill Shopping Centre in June last year.

The firm was also ordered to pay #3,578 in costs after magistrates heard how bolts were found to be missing from the grill where the food was prepared.

Councillor Karen Shakespeare, Dudley’s cabinet member for the environment, said the local authority was very pleased with the outcome of the case.

"We will not hesitate to take action in cases where customer safety is put at risk," she said. "It is essential that all food businesses, whatever their size, have sufficient procedures in place to ensure that foreign bodies cannot enter food and that staff are adequately trained in those procedures."