In message , "David (in
Normandy)" writes
Anyone recognise this small tree please?
It is approximately 15 to 20 feet high and covered with lichens. It has
small blue/grey berries on it, which are mostly pip with a very thin pulp.
The pip is very hard and firmly attached to the thin flesh.

Pictures at:

http://www.avisoft.co.uk/MysteryTree.jpg

http://www.avisoft.co.uk/MysteryTwigWithBerries.JPG

http://www.avisoft.co.uk/MysteryBerryCutOpen.JPG


People have suggested plum (Prunus domestica var. domestica), bullace
(P. doemstica var. insititia) and blackthorn/sloe (P. spinosa). There's
also greengage (P. domestica var. italica).

Blackthorn is usually a hedgerow shrub. It has spiny twigs, while the
others are either not spiny or only sparsely so. Another means of
distinguishing them, not useful at this time of year, is that the
blackthorn flowers before the leaves open, and the others after or as
the leaves open.

[Data from Stace, New Flora of the British Isles, 1st edn.]
--
Stewart Robert Hinsley