Flawless guest service is the foundation of every 5-star hotel in London. From the minute you arrive, staff attend to your every whim, whether arranging valet parking or providing in-room beauty treatments. On top of that, hotels have to offer upscale amenities to be eligible for a 5-star rating. These can include luxury bathrobes, an on-site spa, swimming pools, fine dining restaurants and knowledgeable concierge.