Whichever of beech or hornbeam best suits your conditions. Once established, an annual trim to top and shape sides in summer will result in a hedge which probably keeps its leaves over winter in any but the most extreme conditions. I guess re-laying might be needed maybe every 20 years or so.
Hawthorn and / or blackthorn work but will need trimming and occasional re-laying. (Don't have blackthorn next to livestock, its thorns cause problems with feet and mouths.) If the conditions suit, you could include some holly in the mix. If you don't mind whether it's native or not, and it's not next to livestock, firethorn would add interest and impenetrability, and grows faster so would establish a hedge quicker than hawthorn alone.
If not adjacent to livestock, yew makes a magnificent hedge, evergreen of course. An annual trim keeps it tidy. But it's not a fast growing plant so will take quite a while to establish.