I need someone to correct me if I am wrong (no problem of that here, I think) but cars in the US are supposed to be built with a slight pull to the right. The reason for this was that if the driver fell asleep at the wheel the car would then drift onto the shoulder rather than into oncoming traffic. Since the UK drives on the other (I did not say wrong) side of the road wouldn't a slight pull to the left accomplish this same thing. Just thinking out loud. Might be completely wrong about this.