What on earth is this?

[Tomw84]

And how can I get rid of it?

 

[opps]

Is it live?

If yes, you might be able to put a blanking plate over it.

 

[flameport]

It's the remains of a light switch.
The front plate has been totally smashed off, leaving only the terminals and back cover.

If that's still connected to the supply, dangerous live parts are exposed.

If it's still needed as a light switch, then any standard plastic switch can be fitted there as a replacement.

If not required, then those wires must be isolated wherever they go to (at the light or similar).

 

[Sureitsoff?]

its the rear part of a switch. was there a working switch in that position as it may still have volts across the terminals so be careful

 

[Tomw84]

I've switched the power to that circuit off and won't be switching it back on any time soon!

I actually took the front of the switch off myself cos it was coming away from the wall. Was hoping it'd just be a case of putting a new screw in, but now I'm extremely confused? Is this type of light switch even legal? It doesn't seem to be grounded and doesn't have either the new or old wire colours - both wires are black.

 

[opps]

It was probably legal at the time that it was installed.

Edit- I am guessing that the back box is the round conduit. You might be able to run a earth if you can access it from above (and gain access to the light fitting)

 

[flameport]

Is this type of light switch even legal? It doesn't seem to be grounded and doesn't have either the new or old wire colours - both wires are black.

It's not illegal.

The earth connection (ground) is via the metal backbox. The terminal stud in the centre of the box is where an earth wire from a metal switch would be connected. A plastic switch doesn't need that.

The wires are both black as it's probably wired in MICC, most likely 1960s. One of them should have a red sleeve or disc on it, however that may have been lost or was never installed.
The shiny steel bracket in the box is a later conversion adaptor to allow modern (as in 1970s+) switches to be fitted.

This is a suitable replacement switch: https://www.screwfix.com/p/crabtree-capital-10ax-1-gang-2-way-light-switch-white/24275
One wire in the COM terminal, the other wire in L1.

 

[Tomw84]

This is a suitable replacement switch:

Thanks for the advice - all sorted now!