I well remember the controllers at some larger units going on strike in about '81; I also remember the local union rep at Farnborough (HR) being 'harassed' by the union co-ordinator because he wouldn't insist on Farnborough controllers taking part; left it to individuals to make their own minds up. Then the Farnborough tels supervisors, not NATS employees but in the same union, went out on strike meaning the techies couldn't operate the radio and radar gear. But they couldn't stop us using the runway caravan which had battery powered radios and was plugged into the mains when in position thus the batteries were constantly re-charged, so we carried on with no radar.