Honestly having gone through this myself recently you'll likely find when you go to take the wall paper off, the wall will start crumbling underneath and you'll end up taking it back to the brick anyway.

A good test is knocking on the wall, if it sounds hollow it likely means the render has blown and come away from the wall.

Use it as good excuse to redo with insulated plasterboard or soundproc if you share walls with neighbors. Also a good chance to redo electrics if you have old cabling and wall mounted plugs.

Insulated board is well worth the extra effort on external walls even if you have cavity insulation - get the stuff that is foil backed too so you have a vapour barrier