If you are in London for the spring/summer or even autumn months, then be sure to check out the numerous Royal parks that dot the capital. Hyde Park - the city's largest, covers a vast area from Marble Arch to South Kensington and adjoins with other parks in the city. Explore the Princess Diana memorial or row a boat on the Serpentine.

My other recommendation would be Green Park, it has a better location right next to Buckingham Palace. Deck chairs are available to rent (£2 for 4 hours) and many food shops nearby mean that you won't go hungry. Great for running or relaxing - take advantage of London's green parks.