It's been a eventful century - from the bustling docks of the British Empire, to the devastation of the Blitz, to the collapse of shipping thirty odd years ago. Now the PLA's remit covers everything from leisure craft to environmental duties.
Their web site, here, is a storehouse of information about the goings on on the Thames, including:
And this weekend this centenary is a central part of the Thames Festival, with fireworks, feast on the bridge, river pageant, and classic yachts rally.
If you're in London its definitely worth checking out.