Posted: 26/02/2016 at 07:56
It's the most common question asked on here I think! Obelixx is right Ritchie - if it grows fast, it needs cut more often or you'll have a monster.
If you want a formal look, yew is popular, or even standard privet, but something which gives more benefit to wildlife, as already suggested, is a nicer choice.
Hornbeam and Beech aren't evergreen but retain their leaves over winter to give a screen. They grow fairly quickly if planted in decent ground, but are also easy to keep tidy.