Wall is line with door is the main wall of the house.
This is effectively a 2.5 brick wide extension, with a concrete flat roof above. There is therefore no load on the wall above (except for the roof).
There are no other signs of cracking anywhere else in the building. The crack show is approx 5-6mm wide at the top course of bricks. I suspect that the wall hasn't been painted for many years.
Is it just a matter of filling, and seeing it it moves again, or should anything else be done. What is likely to have caused it?