I work half a mile away from what allegedly is the most profitable junction box in the country. IIRC, the article I read about it a while ago claimed it generates more than half a million quid a year in fine revenues for Kensington & Chelsea Council. That’s one camera at one location.
FWIW, I don’t disagree with fines for blocking junction boxes, because even one driver being stupid or selfish enough not to wait for the traffic in from to move forward, and then being left stuck in the middle of the junction when the lights change will cause cause a disproportionate amount of congestion even for one odd-minute. The problem is that many drivers in London are now scared of being fined, and ignorant of the fact that it’s perfectly legal to wait on a junction box with green lights when intending to turn right, so long as you have cleared the box when the lights go green for the perpendicular direction traffic. So many folk remain timidly outside of the junction box until the traffic on the opposite direction lane stops, sometimes resulting in no more than one or two bloody cars clearing a busy junction per traffic lights sequence.
It is also true local authorities have used the rules as a way to raise revenue in the most ruthless way. Such as in cases when the offending car had been left standing with just its back wheels and arse end of the vehicle standing over the edge of the yellow box.
Technically a valid infraction, but as much of a cunt’s trick as, say, a cyclist arriving home and mounting a deserted pavement with their front wheel for half a metre whilst still riding the bike instead of fully dismounting whilst still on the tarmac and lifting the bike onto the pavement.