Can anyone recognise this plant? Think it’s a fruit tree…

[MeOnSea]

This lovely little tree has appeared over a couple of years in an old pot. It’s just finished blossoming (delicate white flowers) and its bark is a darkish reddish brown.

Is it some sort of plum? Something else?

Would like to plant it in the garden, but want to know what it is first….

if you squint you can see the remains of the last bit of blossom in the first photo

thanks for any advice

It looks like some kind of plum to me. Plums blossom early ( my damson is covered in blooms whereas the apple doesn’t have any leaves yet).