@AC - Re: @ElReg!comments!Pierre = @Hugh Pumphrey - Track Stand? Bah.
> It's not illegal for a car to stop in an advanced stop box,
Fine (this is El Reg I should have expected pedantry!)
*IF* a vehicle has *already* crossed the first Stop line under green and *then* the lights change after they have entered the marked area, but *before* they have crossed the Advanced Stop line then, yes, they are not stopped illegally, although they should not have proceeded across the first Stop line if the junction ahead is blocked.
Highway Code paragraph 178
Advanced stop lines. Some signal-controlled junctions have advanced stop lines to allow cycles to be positioned ahead of other traffic. Motorists, including motorcyclists, MUST stop at the first white line reached if the lights are amber or red and should avoid blocking the way or encroaching on the marked area at other times, e.g. if the junction ahead is blocked. If your vehicle has proceeded over the first white line at the time that the signal goes red, you MUST stop at the second white line, even if your vehicle is in the marked area. Allow cyclists time and space to move off when the green signal shows.
Laws RTA 1988 sect 36 & TSRGD regs 10, 36(1) & 43(2)
However in the vast majority of cases, it is simply a case of an ignorant (or uncaring) driver stopping at the Advanced Stop line instead of the first one.