You are approaching a yellow box junction and can see that traffic is queuing beyond it, with vehicles standing still and their engines idling. Your exit lane is not yet clear, but the traffic light is green. From both a legal and environmental point of view, what should you do?

Explanation

Under Rule 174 of the Highway Code, you MUST NOT enter a box junction unless your exit road or lane is clear, except when turning right and only held up by oncoming traffic or other right-turning vehicles. Entering and blocking the box can trap vehicles in the junction, forcing everyone to idle for longer and increasing emissions. By waiting behind the box until there is space for your whole vehicle beyond it, you comply with the Highway Code and help reduce stop–start congestion and unnecessary idling, which supports better air quality and environmental responsibility.