anyone can identify this tree/shrub?

[Honneybunny]

ok, i am not much of a gardener...
was putting out our bins this evening when i noticed that there is a tree/shrub growing in our hedge that is bearing fruits at the moment. they are dark purple-ish with plum like stones inside. the flesh is yellowy-orange colour. they taste a little sour (i tried , please tell me they're not poisonous... blaaaaaaarghhh ). what could it be. have honoustly never noticed this tree even though i have been here for the last 7 years!!!
some sort of plum?

Damson? They only fruit every 2yrs and wont be ripe yet (and even when ripe can only be really used in jam or wine...)

Hedge though? Implies bush rathger than tree?

Err.... sloes? Does tree/bush have blossom in spring?

hi thanks, have looked up both on google. the fruits are oval in shape, look like small plums, and dark purple/blue. it blossoms in spring. it is a rather wild wide and high (~4m) hedge between us and neighbours. i am thinking damson, aren't sloes much smaller??

Blackthorn?