HFF!

To explain.. this means 197.5 Km from the start of the motorway, in a direction away from London.

Also, to explain, if I was stranded there due to mechanical failure, I would be stood on the other side of the barrier, and behind the broken down vehicle (so it would be in the photo).. In this case I was there for work, with an appropriate and suitably equipped vehicle stood behind me for safety.