The sandwich was named after, but not invented by, John Montagu, Earl of Sandwich. (AUDIO: In the Year of the Cat) The Fifth Doctor claimed to have invented the sandwich. (AUDIO: Fallen Angels)
Types of sandwiches
Protein-filled sandwiches
In 1963, during the Shoreditch Incident, Ace ordered "four bacon sandwiches and a cup of coffee" at Harry's café whilst in London. (TV: Remembrance of the Daleks)
Whilst engaging in a sword fight with the Master, the Third Doctor ate one of his sandwiches. Later at HMS Seaspite, the Doctor also ate a plateful of cheese sandwiches that Captain Hart had brought for Jo Grant, leaving her only a lettuce garnish. (TV: The Sea Devils)
In the 2000s, whilst working late in Torchwood Three, Toshiko Sato made Owen Harper a cheese and pickle sandwich. (TV: Meat)
On the day he died in 2010, Donald Babinger ate a cheese sandwich, which he shared with a pigeon. (PROSE: Apollo 23)
In the mid 2010s Alice Obiefune once made tuna sandwich. (COMIC: Midnight Feast)
Whilst hiding in the Doctor's TARDIS, Klov Dreb Fotch Passameer Day Slitheen III stole, among other food, cheese sandwiches. (WC: Who Ate All the Biscuits?)
In 2018, following her regeneration, the Thirteenth Doctor craved fried egg sandwiches. (TV: The Woman Who Fell to Earth)
In 2018, Graham O'Brien carried a cheese and pickle sandwich because of little time to stop for food when travelling in the TARDIS. (TV: It Takes You Away)
In 2050s New Britain, the Eighth Doctor, Charley Pollard, Viola Learman and Major Ferdinand made and ate sandwiches, some containing smoked salmon, whilst being held by the Daleks in Mariah Learman's palace. (AUDIO: The Time of the Daleks)
Vegetable-filled sandwiches
In 2008, Clyde Langer's cold chip sandwich scared Kist Magg Thek Lutiven-Day Slitheen in his disguise as Tim Jeffery. This helped Sarah Jane Smith figure out that vinegar was a weakness of the Raxacoricofallapatorians. (TV: Revenge of the Slitheen)
In 2050, Alistair Gryffen reminisced about going to a cafe which served "the best baked bean sandwiches in London." (TV: The Bounty Hunter)
The Sixth Doctor's favourite sandwich consisted of peanut butter, lettuce and potato chips. (PROSE: Timeshare)
Others
Lizzie brought a bag full of peanut butter sandwiches with her when she ran away from home. She accidentally dropped one in the TARDIS control console, causing the Thirteenth Doctor's TARDIS to malfunction. (PROSE: The Runaway TARDIS)
Iris Wildthyme once ate a sandwich she bought from a dodgy motorway services, causing her to come down with a lurgy that was currently spreading across the solar system in the 30th century. After going to a hospital in Holby Space City, being cloned and shrunk along with a Professor and PAND-R, with those clones going inside Iris on a "Fantastic Journey", the source of the lurgy was a giant prawn. (PROSE: From Wildthyme with Love)
Sandwiches and culture
Department Regulation 29d forbade the use of unapproved sandwiches at a picnic. (TV: Fear Itself)
Lacking a penny, Artie Maitland gave Embassario Webley a sandwich for a chance to play his Cyberman at chess and win five imperial shillings. (TV: Nightmare in Silver)
As a restorative
The Second Doctor started eating a sandwich in the TARDIS whilst resting after defeating Salamander. He stopped eating it when the Great Intelligence's web started ensnaring the TARDIS. (TV: The Web of Fear)