All Network Radio
Like most industries, radio was more unionised in the 70s than it is today, in both the BBC and commercial sectors.
The early days of commercial radio were frequently troubled by strike action, as was often evident with days of jolly back-to-back music, punctuated with announcements. On occasions, the management stepped back onto the coal face. I recall one day when Trent management sought to sustain programming whilst their staff placarded outside: the MD hosted a memorable news bulletin in which he declared 'we've called the fire police and ambulance service, and all is quiet". Another manager linking songs declared 'I've been on here for eight hours, I'm off for pizza, see you after a few songs'.
ABS, the Association of Broadcasting Staff (ABS) was a union which enjoyed wide membership. When Radio 2 proposed 24 hour broadcasting in 1978, the Union naturally expressed a view of its members' new graveyard shifts. This led to December industrial action, and the new schedule being delayed. Across the period, the BBC national service came together as a single national service - the 'All Network Service', or 'Radio 10' as it became known.