[Red to black]

As so far as regards BC bayonet fittings are concerned, it is has been a number of years that the connections are not live until both pins are depressed by the insertion of the lamp.
So these are not the 'death traps' most people wrongfully perceive them to be, I can't recall off-hand when these were introduced, or if it ever became mandatory in the UK, but that is more to do with my lack of interest rather than anything else, just that we fitted what was available and presumably compliant with current standards of the time, I will need to look this up at some point.
Another poster up-thread also mentioned this.