The story in the press about this insinuates David Cameron might have done this as it is apparently a Bullingdon Club (which Boris Johnson was also a member of) “thing”.
It would be quite surprising for someone who went into Labour politics to do this:
https://www.mirror.co.uk/news/uk-news/bullingdon-club-initia...
When I went from contractor to permanent at my last employer the goal-setting really stressed me out as I knew I didn’t want to be held responsible for something that might change.
In the end I just decided to stop thinking about it to avoid the stress and my manager stopped asking. End of the year I filled in suitable goals based on what I had done and explained how well I’d met them.
It worked very well for me and I did the same for every year I was employed there.