Sunbathing naked in a public place (that includes your own garden) can be done, but if you want to get away with it you might have to brush up on the law.
The British Naturism handy guide to Public Place Naturism has the following to say:
There is no general prohibition of nudity and Naturism is not a criminal
offence, per se. Nudity is legal in a much wider set of circumstances than is
sometimes assumed and “a balance needs to be struck between the
Naturist's right to freedom of expression and the right of the wider public to be
protected from harassment, alarm and distress” (Crown Prosecution Service
(‘CPS’) Guidance on nudity in public).
Every case of nudity is considered on its facts. According to CPS Guidance,
unless there is a sexual context or intent to cause alarm or distress then “it will
normally be appropriate to take no action unless members of the public were
actually caused harassment, alarm or distress”. Even in these circumstances
“regard still needs to be had to the question of whether prosecution is in the
See the full text at: