In the eighties I purchased an LED which had a simple electronic switch somewhere in the wiring so that when connected to a 12V ignition switched supply it flashed when the ignition was off, and stopped flashing when it was on. I can only remember two wires, but you know what memories are like. I drilled a small hole in the top of the column shroud and it was very convincing.
2005 Red Roadster Series 1
2012 Yellow 4/4 2 litre 75th Anniversary