It has been the food of monarchs and commoners ever since John Montagu, the fourth Earl of Sandwich, first pressed some meat between two slices of bread and took a bite. Billions of butties later, the fast-food giant McDonald's has set its sights on his invention. The company has filed patents in Europe and the US that claim the "method and apparatus for making a sandwich" as its intellectual property.

Patent application WO2006068865 relates to the "pre-assembly of sandwich components and simultaneous preparation of different parts of the same sandwich". It covers the "simultaneous toasting of a bread component" and heating a "meat and/or cheese filling". And it says the company has invented a way to add garnishes and condiments using a "sandwich assembly tool".

The patent says McDonald's wants to cut down on the time and labour required to put its sandwiches together. The company also wants them to look and taste the same and has come up with what it describes as "novel methods" to put them together.

The assembly tool contains a "cavity" into which the sandwich-maker places the garnish ("including, but not limited to, lettuce, onions, tomatoes, pickles, chilli, coleslaw, giardinera, peppers, spinach, radishes, olives, egg, cooked bacon and cheese") and the condiments ("ketchup, mustard, mayonnaise, sauces, relish, oils, salt, pepper, barbecue sauce, steak sauce, hot sauce, dressings including salad dressings, yogurt, butter, margarine and liquid or semi-liquid cheese").

A "bread component" is then placed over the cavity and the assembly tool "inverted" to tip out the contents. "Typically, a sandwich filling will thereafter be placed in the bread component," the 55-page patent explains. "Often the sandwich filling is the source of the name of the sandwich, for example - ham sandwich."

It also describes how to make cocktail sandwiches, by taking a full-sized version that is "cut up into smaller pieces".

Lawrence Smith-Higgins of the UK Patent Office said: "McDonald's or anyone else can't get retrospective exclusive rights to making a sandwich. They might have a novel device but it could be quite easy for someone to make a sandwich in a similar way without infringing their claims." McDonald's would not comment.