(Not recommended at home kids) use a key (or, safer, an upside down UK Earth pin) in the Earth hole to open the Live/Neutral shutter - then insert the EU prongs. The width of the EU prongs is handily the same as the UK holes.
Touring musicians do it if venues don’t have convertors.
Doesn’t work if the EU plug needs a live earth of course.
Touring musicians do it if venues don’t have convertors.
Doesn’t work if the EU plug needs a live earth of course.