Left Hook.

Can Anyone explain the arrival of a left hook with the driver? I set up to the same routine always,i.e. good grip, stance, knees, square shoulders and club face. Every now and again this left hook arrives and I dont seem to have made any changes to the above setup. All comments appreciated.

Regards,
Robert

Pulls / hooks - may be caused by keeping your weight on your back foot on the downswing.

It may also be caused by not having enough weight on your right side at set up. You may need to lean more away from the target. This opens the face slightly, a helps keep the face square at impact rather than closed which produces a hook.

I would check clubface at address to make sure it is square, sometimes you can take your grip with the face closed which will cause a hook.
Also, make sure the ball position is where it should be, too far forward and you will either hook or pull slice.

Ball position is huge. It is also important to stay behind or even with the ball. Don't lunge forward on the downswing. Increasing spine tilt away from the ball, like said above, will get you more behind the ball and get more weight on that back foot.