Stan, I worked at Marconi's in 1964 when they were altering the Machine shop, moving lathes, drills etc.to improve the flow of work.
I had to sign the Official Secrets Act, but their secrets were safe with me, I hadn't a clue what they were making.
I worked maintenance with Reg Bastable, who was also ETU shop steward.

A lady lived next door to my mother worked in the canteen, she asked the manager why they bought so much Macaroni when it was never on the menu.
The manager explained that it wasn't Macaroni but Marconi on the boxes.