Goose and Ganders
First off, no politician (or authority in general) should even be permitted to make proposals like this until they themselves are already properly accountable.
That should be a statement of the bleedin' obvious but obviously isn't, which is why I keep having to say it.
Second, particularly in the higher end of the IT field which this appears to target, the notion that capturing computer based activity correlates with the value of any work being done betrays complete ignorance of the creativity which adds the real value to any project. This is related to the earlier comments which touch on the difference between quantity and quality. Yes, we've all had intense sessions where we pump out thousands of lines of code which all looks very productive (till you run it) But equally, I can sometimes spend hours looking at a blank screen, or perhaps a simple diagram on it, or even playing a mindless game, while trying to solve a problem, which eventually concludes with me typing one or two lines of code which achieves the desired result with elegance.
Third, there are definitely use cases where such direct surveillance is justified, though sometimes we're lucky it wasn't enforced. Think Edward Snowden! More importantly, one of the measures that should be mandatory alongside GDPR is that anyone with access to sensitive data which isn't their own should be obliged to keep a private encrypted copy of their machine activity, periodically snap-shot and hashed to a publicly available immutable audit trail; so that in the event of any challenge to their handling of that data, they are in a position to prove their innocence, if necessary "in camera" to a trusted jury. However, should they be challenged and refuse to make that evidence available, we should be entitled to assume their guilt.
(this concept is argued is somewhat more detail here)