"Ian Jelf" wrote

What I meant here was that places like the toilets at Euston could have
restrictions placed on them by their owners which are independent of any
legislation or lack of it prohibiting photography in the street.

As it happens, I wonder vaguely about taking photographs in public parks
now, too, since they;re public places but private property and the
owners (local authorities) could restrict what goes on there.

A public place is one to which the public are admitted, whether on payment
or otherwise. The 'or otherwise' can encompass restrictions on what the
public can do there (the stands on the Centre Court at Wimbledon are a
public place, but the public are admitted subject to restrictions on flash
photography and mobile phones; a cinema may be a public place, but have
restrictions on taking in your own refreshments). In the case of a public
park owned by a local authority any restrictions have to be spelt out in
byelaws approved by the Home Office. However, the Public Order Act creates
the offence of 'in a public place using threatening, abusive or insulting
words or behaviour whereby a breach of the peace was likely to be
occasioned' and someone taking photographs of children so that their parents
took exception could well fall foul of this.

Peter