On Thu, 08 Apr 2021 11:48:50 +0100, NY wrote:

snip

Box junctions at side junctions work well, apart from one little flaw:
you can be on the major road, with traffic from a side road on the left
obliged to give way to you. And you stop at the box junction. As soon as
the traffic ahead moves, a car on the side road turns left and occupies
the space. And then another one does when the traffic moves again. And
you on the major road are stuck there like a lemon, never able to go
because no-one on the side road gives you the priority that the HC rules
decree.

The actual rule is you may not enter the box if the exit is blocked by
stationary traffic. Once the traffic starts moving you may enter the box.
Stopping in the box because the traffic in front has subsequently stopped
is not an offence.