Marks And Spencers new Steak and Blacksticks Blue sandwich – very rich, very flavoursome (and a lovely combination of tangy cheese, sweet onion relish and steak which manages to hold its own against both). Also very expensive – though it will fill you up. M&S’ may have bad ads but their limited edition sammich program has been a treat lately. 

Related and invaluable: sandwichguide.co.uk