Protein shakes are all the rage for people who want to get big and strong - and now rodents are joining in.

Health inspectors found an enormous "super-mouse" during a visit to a Tesco store in central London, a court has heard. It had been gorging on food stacked up in the store rooms of the Covent Garden shop and the inspectors said it was much larger than a standard mouse - although they did not say how much larger.

Droppings, described in court by inspectors as "enormous", were discovered all across the warehouse and storage areas after staff failed to fix doors and pipes.

Super-sized mice were photographed inside food crates, munching their way through kilograms of stock meant for shop shelves and customers' shopping baskets.

The vermin also gorged on the shop's baked goods, helping them swell to unnatural sizes.

One chicken was found covered in droppings in scenes so bad they cost the manager of the store his job.

The supermarket at the centre of the scandal attracted 55,000 customers a week, the court heard.

At Westminster Magistrates Court, Tesco pleaded guilty to six food hygiene charges in a case brought by Westminster Council. Magistrates referred the case to crown court for sentencing.

Mark Watson, for Tesco, said: "I make an unreserved apology on behalf of the company for the conditions of the premises and the offences that arose from these premises.

"Its 3,100 stores do generally maintain very high standards.

"There was in the aftermath a full review of management structures and maintenance staff. The store manager was replaced and full retraining of all staff took place."

Paul Sharkey, for Westminster City Council said the high street giant had failed to call in pest controllers despite being ordered to.

He said: "The officers inspected the bakery and found a large number of mouse droppings on plastic storage boxes and 17 mouse droppings where pastry was kept.

"Food debris was also found in the bakery on top of shelves.

"There was poor pest proofing with the suspended ceiling often used by mice in the building as 'runways'."