Narrow Road Sign: warns road users that the road ahead narrows to the left

Where you will see it

Where the left edge closes in on you while the right hand side of the road carries on as it was.

What to do

Move your line a little to the right inside your own lane, without crossing the centre of the road. Check the left mirror for a cyclist you would be squeezing, and if something is coming the other way, slow and stay on your side.