I do love a food market. The most famous one in London is Borough Market in Southwark, which is open from Monday- Saturday. The market has stood on the site since the thirteenth century and is a big draw for tourists and Londoners alike.
The market is a foodie paradise. One tip I would give is to visit on an empty stomach to fully enjoy all that is available.
Borough Market offers a wide supply of delicacies and delights, including pastries, cheese (lots of cheese) and teas. And the fudge. Definitely try the various types of fudge that Whirld has to offer. It is amazing. Seriously.
The market is super busy so I’d recommend getting there early. However a trip there is worthwhile.