were no hotels at all in the City of London, even though the financial firms of the City were one of the London hotel sector's most lucrative sources of custom. But in recent years, over a thousand hotel rooms have opened in the City. Budget hotel chains such as Travel Inn and Travelodge have also been expanding rapidly in London, since the mid-1990s. One of the most expensive hotels in London is The Lanesborough. Originally a private address (Lanesborough House), in 1733 it was converted into St George's Hospital, and began life as a hotel in 1991. Hotels in modern London There is no official registry of hotel rooms in London, but the estimated number of hotel rooms in Greater London in 2010 was put at 123,000. According to figures produced in support of London's 2012 Olympic bid, there were more than 70,000 three to five-star hotel rooms within 10 kilometres of Central London in 2003. The main growth was a huge rise in the number of rooms within the City of London, while Kensington and Chelsea actually had a small fall. This is comparing figures since 1981. The main concentration of luxury hotels is in the West End, especially in Mayfair and Soho. London's five star hotels are quite small on average by international standards. The largest, Grosvenor House Hotel, has only 494 rooms, and eighteen of them have fifty or fewer. The range is very wide, including: Traditional purpose-built grand hotels such as the Ritz, the Savoy, and the Dorchester. Recent conversions of grand late 19th and early 20th-century office buildings into hotels such as One Aldwych and the Renaissance Chancery Court. Townhouse hotels. Modern purpose-built chain hotels. List of Five-Star Hotels in London There are no official bodies that rate hotels. The most widely accepted bodies are the AA (in the past the RAC too) and the English Tourist Board. The ETB has recently changed its criteria to match that of the AA, to provide consistency. Many hotels remain self-rated. Other notable hotels One of the more unusual hotels is the Sunborn London, a floating hotel by the Excel center in East London and constructed specifically as a stationary floating hotel (it has no engine). The original yacht was sold to the Lagos government and has now been replaced with a larger yacht at the same berth. The 3-star 1,630-bedroom Royal National Hotel in Bloomsbury is the