Blown plaster... any remedies?

MrQwest

Over the last year, we've had some wallpaper coming away from the wall and it has started bubbling. Behind the wallpaper, the plaster appears to be cracked, crumbling and falling away from the wall! This is in our lounge and looks rather unsightly. On the other side of the wall is our airing cupboard where our boiler is. The paper in here has also flaked off the wall, but also, the bathroom also backs onto it.

I was unsure as to what this was until recently where i think its blown plaster.

We had an electrician round a year ago to fix our boiler. Our landlord arranged him, and has used him before. he told me that before we moved in (4yrs ago), they had trouble with a boiler that leaked or something.

Could this be what's causing the blown plaster? Or could it be water seeping in from the bathroom? I'd rather get the problem sorted before repairs as opposed to repairing and it happens again in a years time!

Any ideas?