A box junction is a yellow grid painted on the road surface which serves a reminder to drivers not to block the junction.
Ahead and left turning at a box junction
Before entering the box junction, check that there is room for you to clear it. If not, then you must remain behind the white stop line, until you can proceed, even if the traffic lights are on green.
What about turning right at a box junction?
You are allowed to enter the box junction and wait in the centre, as long as the only reason you cannot continue is the oncoming priority traffic. Once there is a gap, or the lights change, you can proceed to clear the junction. Always check there is room before you commit to crossing the white line, or you may be marooned in the box, blocking the way of some irate drivers. On the other hand, some drivers think that they cannot enter the box junction and end up causing delays to drivers behind them. It's essential that you undestand the rules of box junctions and abide by them to ensure that you can safely deal with and exit accordingly. Apply the same procedure for all junctions, with out without the yellow grid.