This video is about the Mullard thermionic valve works in Blackburn, UK, in the 1950s.

I find it all utterly familiar, having been taken on industrial radio factory tours from my college, the Northern Polytechnic in London.

https://www.youtube.com/watch?v=-GgWIlvyEL8

Mullard was one of the major radio and radio valve manufacturers in that time. I can't remember just what dates were milestones for them, but I remember one of our lecturers saying they made a packet during WW2 on the 1154/1155 radio transmitter/receiver sets carried by the bombers of the time. Lovely coloured plastic knobs!. Like many others at one time, I had the receiver  set, which was by way of being a quite broadband communications receiver. It included a direction finder function, for which there was a special antenna.  I think this section was normally removed before the set was sold as government surplus.

Mullard valves were identified normally by the European nomenclature, so that a 6V heater double triode would be called an ECCxy, where E was the 6V, CC =two C, triodes, x was the base type and the y was the individual valve characteristic.