Lettuce is incredibly well suited to moist and cool the British climate, making it an essential inclusion in your plot. Little Gem one of the most famous of all, renowned for its sweet, dense and crunchy hearts.
Great raw in salads, and also wonderful quartered and braised.
It's not a 'cut and come again' lettuce like lollo rosso so it will require repeat sowing every month or so if you want a constant supply.
Because of it's small size it's particularly well suited to windowboxes and containers.