White Bryony Bryonia Dioica
There are various members of this group of plants growing in Europe and Asia, but this one is native to the UK. A distant relative of the Cucumber; it likes to climb through hedges or small trees, quite common in south East England, but also being present in Chalky or Lime stone areas.
The Flowers and vine-like climbing stems, which continue to flower throughout much of the Summer; usually go unnoticed, as they are fairly undramatic and blend in with their surroundings. But it is in the Winter when this plant suddenly becomes the centre of attention, with these dramatic orange/red berries, draped through tree branches and bare Winter hedges.