Fields in Trust is a British charity[1] set up in 1925 as the National Playing Fields Association (NPFA), by Brigadier-General Reginald Kentish and the Duke of York, later King George VI, who was the first president, which protects parks and green spaces and promotes the cause of accessible spaces for play, sports and recreation in British cities and towns.

It is also linked to many other bodies, and the members of the organisation include local authorities, individuals, playing field associations, schools, and sports clubs.

In 1972, Fields in Trust (then the NFPA) supported the Bishop of Stepney, Trevor Huddleston, in denouncing the lack of play provision which had led to the deaths by drowning of two boys who lived in his diocese.

This was with the intention of ensuring "every man, woman and child in Great Britain should have the opportunity of participating in outdoor recreational activity within a reasonable distance of home during leisure hours".

In the 1920s and 1930s many of the sites were funded by the Carnegie United Kingdom Trust on the basis that the land would be kept as public playing fields in perpetuity.

In most cases, the responsible body entered into a Deed of Dedication declaring that the recreation ground shall "be preserved in perpetuity as a Memorial to His Late Majesty under the provisions of the KGFF and shall henceforth be known as a 'King George’s Field'."

Fields in Trust reissued The Six Acre Standard under the new name Guidance for Outdoor Sport and Play in 2015 as an online reference work for planners in the UK.

[further explanation needed] Versions of the Guidance for the devolved administrations of Scotland and Wales were launched in January 2017 as well as a Welsh Language edition.