Thanks for that. Yes, I'm sure all the lights are on the same circuit (covers downstairs rooms and hall but not kitchen/utility) - and none of the other switches in the box were tripped. As you say suspect there is a break somewhere (but not sufficient to cause fuse to trip). Nothing has been...
Would appreciate some guidance (before I get a professional in , no doubt!) on a lighting problem.
The downstairs lighting circuit covers five rooms. Two of the rooms are fine but three have no power at any wall/ceiling lights. This occurred suddenly last night and did not trip the circuit...