Chris Lewis wrote:
what is "metric"/"imperial" about 220V versus 120V?
Answer: _nothing_whatsoever.

Quite. In any case, European voltage is now 230 V nominal (although
220 V is within tolerance). Normal British light bulbs do not screw.
They are bayonet fittings just like those on cars.

The people in the electrical store claim not to understand me when I
ask for a 205 BTU per hour bulb.