A daily service with Thames River Sightseeing calling at Westminster Pier, St. Katharine Pier (for the Tower of London) & Greenwich Pier (for the Cutty Sark & Royal Museums Greenwich). Between April-October Thames River Sightseeing also operate cruises to the Thames Flood Barrier, the 2nd largest movable flood barrier in the world.
It's easy to reach Viscount Cruises, in London, by train. Simply hop on a train to London Charing Cross station and then it's just a short walk to the pier on the Thames.
For more info including times and operating dates, visit Viscount Cruises’ website.