I cant say I'm surprised - 172 in a 40 is taking the piss somewhat, however, is it a worse offence than burgling someone?
http://news.bbc.co.uk/1/hi/england/oxfordshire/7009923.stm
I think you'll find it was 172 in a 70 BTW
Doesn't seem to make much difference really does it? However he could have done with a better solicitor.
I recall a policeman doing something like that but got away with it because he was "Just testing"
I would have demanded jail if he been involved in an incident of any kind, but he wasn't, and seeing as he didn't endanger anyone or injure anyone I would have denied the dangerous driving charge based on lack of any relevant evidence.
Driving without due care and attention? No. I'd say he was giving it his full attention. Speeding? Yes, Guilty m'lud fair cop.