Carlton Reid has put together a great video with Chris Boardman and Blaine Walsh to help illustrate Rule 163 of the Highway Code.
Highway Code Rule 163
Overtake only when it is safe and legal to do so. You should
- not get too close to the vehicle you intend to overtake
- use your mirrors, signal when it is safe to do so, take a quick sideways glance if necessary into the blind spot area and then start to move out
- not assume that you can simply follow a vehicle ahead which is overtaking; there may only be enough room for one vehicle
move quickly past the vehicle you are overtaking, once you have started to overtake. Allow plenty of room. Move back to the left as soon as you can but do not cut in - take extra care at night and in poor visibility when it is harder to judge speed and distance
- give way to oncoming vehicles before passing parked vehicles or other obstructions on your side of the road
- only overtake on the left if the vehicle in front is signalling to turn right, and there is room to do so
- stay in your lane if traffic is moving slowly in queues. If the queue on your right is moving more slowly than you are, you may pass on the left
- give motorcyclists, cyclists and horse riders at least as much room as you would when overtaking a car (see Rules 211 to 213) and 214 to 215).