When you arrive in London, you can get good information at the Travel Information Centre near the Eurostar arrivals area at St. Pancras International train station and at Victoria and Liverpool Street stations. These are helpful if you're looking for brochures for London sights, or if something's gone horribly wrong with your hotel reservation—if, for example, you don't have one—as they have a useful reservations service. The Victoria station centre, opposite Platform 8, is open Monday–Saturday 7:15 am–9:15 pm, Sunday 8:15 am–8:15 pm, as are the St. Pancras and Liverpool Street centers. A Travel Information Centre at Euston station has the same hours but closes Saturday at 6:15 pm, while one at the Piccadilly Circus Tube station is open daily 9:15 am–7 pm. The Travel Information Centre at Heathrow is open daily 7:15 am–9 pm. There are also London Tourist Information Centres in Greenwich and some other Outer London locations.
London Tourist Information Centre (Victoria Station Forecourt, Victoria, London.)
VisitLondon (Victoria, London. .)