Definitely included this pub on a couple of our London pub crawls in the past, just round the corner from the Chandos (Museum Ale) if my memory serves me correctly. I'm sure its a worthy winner!
If its London pubs then these days I always seem to end up around the Southwark area. The list of decent real ale pubs is really worth considering:
I add the Royal Oak mainly because of the food I had there, Roast Rabbit with mash, but the beer was excellent too.
The best pubs here would probably be:
Market Porter: Excellent pub always with at least 6-8 real ales on, which they constantly change!
George Inn: For it history ... and its beer!