However, there may yet be a spanner in the works. Ecologists have found a large number of lizards and slow worms on the proposed site, which may have to be rescued before construction could begin.

via www.kentonline.co.uk

Emphasis mine. 

May have to be rescued? If appropriate mitigation is not undertaken and reptiles are subsequently killed, The Royal Mail could be prosecuted for committing an offence under the Wildlife and Countryside Act. Presumably may will turn to will before this scheme goes forward.