Plum tree - what type is it?

I've got an ancient tree in my garden that produces fruit at this time of year. They grow in clusters, and look like small round plums, burgundy/green skins with a plum like stone in the middle, but a distinctive peachy taste. I've also got a Victoria plum tree and these are different. Any ideas please?

Plum tree - what type is it?
It sounds like Damson, probably either D. Farleigh or

D Shropshire.
Reply:Nectarine
Reply:From your description it sounds like a Damson. Great for making Jam.
Reply:Greengage?

or are these perhaps another variety of plum, such as Warwickshire Drooper (an old variety of plum a bit like a Victoria but sweeter).
Reply:Possibly damsons, we have a tree we thought was aplum, but the fruit are smaller and purply in colour.
Reply:It could be a pluot- that is a cross between a plum and an apricot. It look most like a plum. Sorry I don't know variety names. A picture might be helpful.