The Jerusalem is both fabulously historic and a complete fabrication. Although the premises date from the early 18th century, the current shopfront wasn't added until 1810 and the place didn't open as a pub until the 1990s.
The wonky, green-painted interior has two front tables and a fireplace partially screened off from the main room, which has a large fixed table at the back and a sweet little table above the friendly melée of lawyers, media workers and businessmen.
The beer in question is the full range from the St Peter's Brewery in Suffolk, served from a row of small wooden casks lined up behind the counter. The decent food offerings include a large roast pork sandwich on sourdough with potato wedges. The place is small, however, so avoid the immediate after-work rush if you don't feel like sharing a table.