I’m starting to compile as many definitions of public space as I can from here.
2011
First, the definition from the London Assembly’s 2011’s report, ‘Public life in private hands Managing London’s public space’, which started to acknowledge the massive shift to privately-owned public spaces in the capital.

‘all spaces including streets, squares and parks that everyone can use and access in principle, regardless of who owns or manages the space’.
2004
The 2011 report also quoted the 2004 government report, Living Places: Caring for Quality, https://www.futurecommunities.net/files/images/ving_Places_Caring_for_Quality_Report__ODPM_.pdf, which defines ‘public realm’ as
‘all those parts of the built environment where the public has free access. It encompasses: all streets, squares and other rights of way, whether predominantly in residential, commercial or community/civic uses; the open spaces and parks; and the ‘public/private’ spaces where public access is unrestricted (at least during daylight hours). It includes the interfaces with key internal and private spaces to which the public normally has free access’.
1990
The 2011 report notes ‘this is different from the legal definition in the Town and Country Planning Act of 1990’ (https://www.legislation.gov.uk/ukpga/1990/8/section/336)
“open spaceā means any land laid out as a public garden, or used for the purposes of public recreation, or land which is a disused burial ground’
and the more traditional planning definition of Public Open Space.
It also notes the additional category of ‘public green space’, including urban parks and gardens, country parks and canal and riverbanks.
2014
See also the 2014 government guidance about the definitions of Open Green Space in replation to planning and sport: https://www.gov.uk/guidance/open-space-sports-and-recreation-facilities-public-rights-of-way-and-local-green-space



Would a court yard surrounded by small individual office unit with a large opening to it in restricted be classed as a public space. I’m asking this as I have a small bar in the court yard. If this would be the case I could serve takeaway beverages many thanks
No if it is on private land
A development was, in the conditions, required to provide 10 percent public open space. The developers said all areas were accessibly open i.e for public access. The subsequent management company backed by some residents have closed much of it near their houses stating POS does not have to be accessibly open it can be an open visual amenity as in the 2014 definition. The Council won’t get involved as its over ten years since completion and there is nothing specific stating how the POS was to managed or if it had to be accessibly open (despite the open space plans showing paths across all areas). If this is legal then it appears any management company can simply decide what areas, if any, are open to access post completion so long as there is nothing specifically stating POS has to be open and accessible. IE It appears Public Open Space can still be Public Open Space even though it can not be accessed. It seems crazy and dangerous to me.
Would Crown Property, for example, Prison Grounds be classed as public access?
No, as Crown Property is private land.
Are pubs considered public space
Hi John. A good question. I’m not classing them in the same category as open public spaces, as they are privately owned and require licenses from the authorities to open. but in a more general sense, they are public.