Axel Keating
From what you describe it may only be cracks on the plaster, it can 'blow' from the bricks. Cracks can be caused by a building settling,if there had been any structural works done to it. Clay soils, drains, nearby excavations can all lead to subsidence. The only definite answer you will get is from a structural engineers survey or a building firm who have expertise in this area. But, from the info you've given..I would not be too concerned.
