On my ‘65 MGBGT it operated the headlights, on everything else it was the choke.
That’s Lucas for you.
I saw a cartoon decades ago that addresses that problem. It showed a crew of astronauts preparing to launch. One of the crew had an absolutely horrified look on his face, as he was staring at a badge above the control panel that read, “Lucas Electrics”
On your MGBGT, it was the Dim, Flicker, Off switch.