Nesting birds
It is an offence under Section 1 of the Wildlife and Countryside Act of 1981 to intentionally take, damage or destroy the nest of any wild bird while it is in use or being built. It will be an intentional act, for example, if you or your neighbour know there is an active nest in the hedge and still cut the hedge, damaging or destroying the nest in the process.
Having looked again at this photo I've realised that it is OUTSIDE the metal fence and was probably chopped - ILLEGALLY - by the council. If it was chopped by the developers without permission then they should be in trouble - but hey ho - who's bothered? Nobody it seems.