UK: Do you legally have to stop before a cycle box line at a traffic light?

At a good percentage of traffic lights, especially in towns, and cities, you will see a cycle box, with a line, separated from the normal traffic light line. Is it against the law for a cyclist, biker, or motorist to bypass the 'first white line'?

(Cc) Dwayne Hards.

Yes, drivers, motorists, and cyclists MUST stop at the 'first white line', however, if the light changes, and is about to turn red, but it is to unsafe to brake before the cycle box line, then it is safer/better to stop in the cycle box than to brake to quickly, or harshly, according to 'The Highway Code'.