How would you like a Ham Portsmouth? Or an Egg & Salad Portsmouth.
A sandwich could have been called a portsmouth, but for a quirk of history.
As many people know the Earl of Sandwich became very hungry in the middle of a card game so he ordered his servants to prepare a bit of meat inside two slices of bread, in order that he could continue his card game without leaving the card table to have a meal. One of his fellow players looked at the snack and decided that he rather liked the look of it, and he too ordered ‘the same as Sandwich’. And so the sandwich was born.
But the Earl of Sandwich is a title, not a name, and the 1st Earl of Sandwich was able to choose his name. He was a sailor and he wanted his name to be that of a famous port. The two biggest ports at that time were Sandwich and Portsmouth. Sandwich was the bigger, so he chose Sandwich as his name. In a twist of fate Portsmouth later became much bigger, and was the base for the British Navy for hundreds of years, so perhaps the earl made the wrong choice.