Mould suddenly appeared on bedroom ceiling?

[passmethewineplease]

So I've noticed there is a bit of what looks like mould in the for corner of our bedroom ceiling, never had this problem before, we rarely dry clothes on radiators and the windows get opened to let the air circulate.

The only thing different is that we've had the room repainted but that wouldn't cause mould would it?!

Mould and mildew remover has not budged it, so I don't think it's condensation mould?

Any ideas MN?!

[wowfudge]

Can you get into the loft to have a look? It could be a dislodged roof tile/slate or a loose ridge tile rainwater is getting under. You may be able to see daylight through in that area of the loft if that's the case or evidence of water damage in the roof space.

When it is raining, can you see whether any guttering in the area is leaking? If so, rainwater may be getting in in that area. Get the guttering cleared and repaired if it's cracked. Also have the pointing checked - if the pointing has gone, water could be getting in between the bricks.