Overboarding thickness - how much smaller will my room be?

I have a lot of woodchip wallpaper and normal wallpaper, all painted over multiple times. Removing it is going to be hell.

So instead I was thinking of overboarding, but how much room will I lose to that? Some of the corridors are only 1m wide.

Presumably I’ll need to put up trusses, screwed into the brickwork, and then plasterboard over those. Plasterboard is 10-13mm thick, plus say 10mm for the truss, on both sides, which suggests the corridor would end up being about 950mm wide at the end, not too bad.

Is that a reasonable assumption or will it be thicker than that?

This is a residential house in the UK. There will be wiring behind the plasterboard, i.e. through the trusses.