The Central Line runs through the city and neighboring area.  The completion of the circle will take you through 27 stations and therefore potentially 27 pubs. This has become a popular challenge for groups to complete for various occasions.  If you plan on tackling it, you had better be prepared to take the day to try it.

It is recommended that you start at either end of the City and make your way through it first as these pubs are often the first to close.