American military scientists have developed a new battlefield weapon: the indestructible sandwich.

It can survive air drops and rough handling to stay fresh for up to three years, even in tropical conditions. Eventually, it is expected to follow freeze-dried coffee, dehydrated egg and processed cheese from the battlefield on to supermarket shelves.

So far, only pepperoni and barbecued chicken varieties have been developed. Soldiers who have tasted them say they are “acceptable”. Scientists are now working on indestructible pocket pizzas, cream-filled bagels and peanut butter sandwiches.