More and more odd!

While I was out driving yesterday I noticed this blossom along a length of hedgerow, but it was getting dark and I couldn't stop. 
So, today I went back to investigate, and I was really surprised to find it was Blackthorn (well i think it is).  The Blackthorn  or Sloe Prunus spinosa is a deciduous tree (or large bush) which blooms in early spring prior to the arrival of it's leaves, now when I say early spring I mean late March ish, and most certainly NOT December! 
This is so odd, the whole bush was in bud and coming into full bloom, I really do hope we don't have a sudden cold snap which will ruin everything!