In message , at 11:21:13 on Thu, 22 Dec
2016, tim... remarked:

I don't see that this position is any different to having a few driver
aids - adaptive cruise control, lane assist, auto breaking etc, all of
which can (and are) happening without any changes in the rules.

Auto breaking is regulated by this SI (as amended):

http://www.legislation.gov.uk/uksi/2.../contents/made
--
Roland Perry