Just a small crack

This started as a small crack. Over the past weeks it got bigger and the plaster looked as though it would collapse under the weight of all the debris that had collected behind it.
Now we know why!!! A leaking gutter has caused the wall to be damp and it has compromised the plaster.
Our builder arrived today to scrape it out. This really did start off as a 10 inch crack. The moral of this is to keep checking your gutters.
What is really annoying is that we only decorated this room last summer.