Help with electrics

I have a problem with my outside light. I thought the bulb had gone but couldn't remove the cover to get to it as all the access screws had rusted up. I ended up removing it from the wall and fitting a new light which then didn't work.

I jury rigged both lights to an internal socket and they both worked.

Back to the outside cable which consists of two covered cables and a bare copper earth wire. There's no voltage registering between the live and positive wires but there is between one of them and the earth. I've checked the switch and there doesn't seem to be anything loose or disconnected inside.

My question is, is it likely to be the switch is faulty or is there something more serious at fault?

Sounds unsafe. Get an electrician.

Is the neutral wire the one you are calling 'positive'?

What colour is the insulation on it?

Could it be that the neutral wire is broken, or maybe disconnected accidently somewhere?

I'm another guy who is not a 'trician, but that's what I'd be checking.

Make sure you have not got an uninsulated live wire now you have taken the light off.

Outside lights need to be protected by an RCD at the fuse board. That’s to protect you in the event of a fault. If you tested the circuit as you described and did not trip the RCD, you may need to update your consumer unit. Get an electrician to have a look.

Having checked everything possible (for an unqualified person) I'll be getting an electrician out so thanks for people's input.

Outside lights need to be protected by an RCD at the fuse board. That’s to protect you in the event of a fault. If you tested the circuit as you described and did not trip the RCD, you may need to update your consumer unit. Get an electrician to have a look.

Not an actual requirement though, the Wiring Regs are not applied retrospectively. Prior tio 17th edition, no requirement to RCD protect lighting circuits, inside or out.