I’ve just rewatched it, for the sake of completeness and the annoying thing is that it COULD have been OK. It started off not bad, missing prototype medicine and the involvement of the “funny ones, who sit in Whitehall and start wars” but went silly. The chase with chucking fish was just ridiculous, and I do remember grumbling about what Morecambe and Wise were doing in this highly professional series, at the time.
I concur with the earlier thoughts. It starts out reasonable enough but descends into the absurd really. The outline story could have easily been found on a Professionals episode with its political angle.