You must be aware of and allow for any off-track when making a left turn. Unless you use your left outside mirror to monitor the trailer’s path, the trailer might hit either a vehicle or a sign post on an island.

You must turn the vehicle in a wide arc before bringing it back to its proper position after a left turn, just right of the centre line; then, as you increase speed, you can move, when it is safe, to the right lane.

Diagram illustrates how to make left turns correctly with a wide arc.

Diagram 2-10