Statutory Instrument No 500 of 2020 comes into force tomorrow - it amends The Health Protection (Coronavirus, Restrictions) (England) Regulations 2020. It says you can
visit a public open space for the purposes of open-air recreation to promote their physical or mental health or emotional wellbeing
A “public open space” is defined as:
(a) land laid out as a public garden or used for the purpose of recreation by members of the public; (b) land which is “open country” as defined in section 59(2) of the National Parks and Access to the Countryside Act 1949(a), as read with section 16 of the Countryside Act 1968(b);
(c) land which is “access land” for the purposes of Part 1 of the Countryside and Rights of Way Act 2000(c) (see section 1(1) of that Act(d)).”
It's as straightforward as that....