The new brew features the London landmark Traitors' Gate and a Tower of London Raven on the pump clip.
The beer will be available in 54 pubs across the Fuller's estate and some in the free trade.
The 4.5% ABV draught cask conditioned ale is made using a blend of Liberty hops from the USA and Galaxy hops from Australia. It is described as being "full bodied with a biscuity malty character, a refreshing citrus nose and subtle palate-cleansing zesty finish".
Fuller's Head Brewer, John Keeling, said; "The brewing team at Fuller's have been successful in producing new exciting ales such as Black Cab and Bengal Lancer that gives our customers extra choice. Traitors' Gate is the very latest, with others being crafted for later release.
"Traitors' Gate was developed to complement our core range of ales and to extend our seasonal ale portfolio. We are very pleased indeed with the end result.
"Our new ruby red ale is full bodied with a tropical fruitiness combined with a sharpness from the rye. It's a beer that leaves the palate with a zesty freshness."