umpston wrote:

I do not believe there are any speed limits of less than 20mph on
public highways in the UK. I doubt the police can specifically enforce
the lower limits that are often signed on private roads and in car
parks, although they might well be able to arrest you for something
else if they saw your fast driving as dangerous.

There is a posted 15mph speed limit on a public road I visit regularly.
As to whether it is legally enforceable, I couldn't say. What are the
criteria for enforceabililty?

I have been told that the boundary of the speed limit needs to be
signed on both sides of the road for it to be correct, valid and
enforceable, and this particular sign is on the left-hand side only.
Does the lack of a sign on the right hand side make it unenforceable?
Come to that, should the opposite face of the sign show the speed limit
in the opposite direction? This one currently doesn't.

Regards,

Sid.