I agree with boy boy, it does look like penetrating Damp!! but I'd say you'll need to replaster the bay area once the problem has been remedied, preferably with a waterproofer added to the cement render (backing coat)

it could be both types ..rising or penetrating damp ...i think its penetrating ..the picture looks like it is a bay window ..corner of ..these are notorious for this type of damp ..you need.. to check outside for two things ..either the wall is rendered and its blown ..the pointing may be defective ..you need to check that the window cill is working right ..pour water on window outside ..it should run down window and run off cill ..the water should not touch the wall ....make sure the ground outside is two bricks lower than the dpc ..make sure gutter is not leaking ....place fan heater into corner to dry out ..kill mold spores with dettol

Its a water damp which will increase gradually Get it repaired early before its spread

Hello,

Can anyone advise what type of damp this is please?

Thanks