HS3 could build on Crossrail's fine example

Crossrail and the Royal Society for the Protection of Birds (RSPB) have demonstrated first class thinking by using the spoil from tunnelling under London to expand wetlands at Wallasea Island. Avocets are one of the beneficiaries, and that is fitting because they form part of the RSPB logo.

Avocet kneeling allowing chicks to find shelter
under wing © Crossrail

There is an argument, based on population densities, that HS3 should run north south tunnel under London with a loop to the east. It would complement Crossrail's east west route.

Imagine using the spoil to build Boris Island Airport and, rather than filling hard earned tunnel space with ballast, providing additional facilities for other services.