Next Saturday (11th July), there will be a chance to wander around HMS St Albans which will be in Docklands on a visit.
Note that due to space restrictions onboard members of the public will be unable to actually see inside the vessel but will be able to tour the upper deck and have the opportunity to see some of the equipment used onboard, weapons systems, and an opportunity to speak with members of the ships company.
In addition members of the Royal Navy Reserve from HMS President will be in attendance to show what the Reserves have to offer.
Visits are timed, and free tickets can be booked here
I took a look around back in 2010 – review here