My '68 has just developed an issue, where the brake lights come on solid with the ignition.....was fine untill saturday.

No amount of pedal pressing changes anything, and they do turn off with the ignition.....which is a bit weird.

What happens when you unplug the MC switch?

sounds likely like stuffed MC switch. yeah do what he says first and let us know.

It's fixed itself.....might get a new switch anyway.