A story......pass on if you don't like stories.
The case most often quoted in time off for TU duties is Beecham vs Beal. It went to the court of appeal. (1982). Beecham became Glaxo Smith Kline Beecham. (Glaxo SK, or GSK).
Beal was an activist ASTMS rep within GSK, and Ian Moore, the then HRD was fed up with Beal. Ian, as an ex-TGWU convenor at the (then) Michelin factory in Scotland, didn't have much time for ASTMS generally. This was in the days when CliveJenkins, the ASTMS GenSec was doing dodgy personal property deals in Camden, using ASTMS money, and most of us in the trade were aware of it. Clive resigned "unexpectedly" in 1988.
(Clive regarded himself as an expert on Aviation)
The case was about Beal attending an ASTMS "conference/meeting" which Ian believed had no direct relevance to GSK. Ian saw it as Beal skiving, yet again.
At that point in time, Ian had a "mate" in the GSK legal team who was assertive, so they thought they'd take on ASTMS about time off for this meeting. Unfortunately for Ian ASTMS used a bright left wing QC who was trying to make a name for himself in the Employment law market, and who saw this case as a way of getting his name known. (Even BA's famous lawyer, Webb, was young once!).
The case went to the Court of Appeal, and Beal won. The Court put quite a wide definition on what "reasonable time off for TU duties" actually was. Ever since then, employers have been careful about when to refuse time off.
Er, except Ian. The next time Beal asked for time off for a very similar meeting, Ian told Beal that he could not have the time off. If Beal wanted to challenge GSK on that point, he could take them to court. ASTMS declined the opportunity to take GSK to court.