Before it was replaced by a bridge, the Tattershall Castle used to paddle from bank to bank on the Humber. Now it's a bar-cum-restaurant moored on the Thames by Embankment tube station. On sunny days it's a fine place to bob up and down on deck; at night the outdoor atmosphere turns palpably, though good-naturedly, laddish, with a barbecue in the summer months and large amounts of pounds 1.90 beer pouring down throats. On the lower decks, a restaurant serves hot and cold food lunch and evening and on Fridays and Saturdays a nightclub runs until 3am. Handy for Westminster pier (boats to Greenwich), Trafalgar Square and the footbridge to the South Bank.

Tomorrow: Wintons Soda Fountain