[mdjlucan]

It blossomed lovely I few weeks ago and this is what's happening anyone know whats. Causing this to happen

[Trikidiki]

I'd suspect it's Plum Leaf Curl. Check for aphids on the bottom of the leaves.

[jaydig]

Mine's gone exactly the same, and despite having loads of blossom there only appear to be one or two tiny fruits on it.  I've checked for aphids but can't find any.  The only thing I can think of is that we had some very cold weather with a couple of night frosts, and I wonder if this has caused the damage.