Blackberry

Thanks, everyone, for your suggestions. It helped a lot.

There are around 300 odd named species of bramble in Britain and Ireland and probably as many yet to be named.Many British botanists (batologists) in the past have specialised in Rubus. Rubus fruticosus (full Species)has no thorns.And the leaf is not right for ulmifolius.Your photo is best named Rubus fruticosus agg.(aggregate)
To the Blackberry picker tho.A Blackberry is a Blackberry is a Blackberry.
Blackberry pie and cream.Cant beat it.