I met up with some friends for after-work drinks at the Britannia and we'll definitely be coming back. There is a very good selection of beer (including traditional ales) and Swedish cider, and there is a decent wine list as well. There is plenty of comfortable seating on leather sofas, chairs, and stools, and unlike many British pubs the Britannia has hardwood floors rather than carpets so there's no sickly stale beer smell. The wood-paneled interior is light and airy with a wood-burning fireplace. It's also open quite late for London - we didn't leave until almost 1am and never felt pressured to move out earlier.
If you own or manage Britannia, register now for free tools to enhance your listing, attract new reviews, and respond to reviewers.