• Highway code rule 160: keep to the left, unless road signs or markings indicate otherwise.
  The exceptions are when you want to overtake, turn right or pass parked vehicles or pedestrians in the road
• Highway code rule 264: Keep in the left lane unless overtaking
  If you are overtaking, you should return to the left lane when it is safe to do so.
• Follow on rule 268: Do not overtake on the left or move to a lane on your left to overtake
  Do not overtake on the left or move to a lane on your left to overtake.
  In congested conditions, where adjacent lanes of traffic are moving at similar speeds, traffic in left-hand lanes may sometimes be moving faster than traffic to the right. In these conditions you may keep up with the traffic in your lane even if this means passing traffic in the lane to your right. Do not weave in and out of lanes to overtake.