On London sites, you may well find yourself building over tube tunnels, DLR or even historic royal mail tunnels. Whilst these may be obvious from title entries, it is worth making appropriate searches. Tube lines are not always obvious as they have branches and turntables extending beyond the usual commuter routes.
Building over TfL tunnels will need a developer to work closely with TfL and enter into asset protection agreements. TfL has strict requirements as to the piling contractor's level of insurance which can seriously limit those companies who can do the works and of course, higher insurance comes at a cost. Getting the documentation right with your contractor means you can back off your risks and limit your exposure under agreements with tunnel owners.
