I would guess what is important is the state of your exit road as you
entered the yellow box (as in "do not enter if ..."). I don't see how you
can be prosecuted for a change in the state of your exit road while you are
waiting for a gap in the oncoming traffic when making a right turn in a
yellow box.
John
"Paul Weaver" wrote in message
om...
I'm a little unsure about the law on box junctions. As I understand it
you can enter a box junction when turning right if the road you are
turning into is clear and when oncoming traffic stops you can proceed.

What happenes if this road then fills up as you are waiting (by
oncoming cars turning left)?

One other question, are u-turns automatically enforced, or is it
leanient (e.g. no fine for uturns on an empty road at 3AM)