Testing the vehicle’s capability, I think it was.
There were a couple of comments about going to jail, I doubt that’s correct- speeding is a civil offence, you need to escalate to a criminal driving offence like dangerous driving don’t you? Speeding isn’t dangerous driving per se. So without reports of something actually dangerous happening while speeding, it’d be bans/fines/etc regardless I think.
(there was a fun case a while back with 2 bikers, both were charged with dangerous driving, but in the end one got the jail for a 100mph+ overtake over a crest with imperfect vision, the other got charges thrown out as all he’d done was go very fast, and they hadn’t charged him with the right offences)