This part particularly is interesting.
The airport scheme promoters have pledged to meet the cost of surface access
schemes required to enable a runway to open. For Gatwick Airport, this covers the full
cost of the works (including the M23 and A23) needed to support expansion. The two
Heathrow schemes would pay for the full cost of M25, A4 and A3044 diversions and
local road works. They would make a contribution towards the cost of the proposed
Western Rail Access and Southern Rail Access schemes. Improvements which are
already underway, such as Thameslink and Crossrail, will be completed, and the
Government has not assumed any change to these schemes’ existing funding.
4.30 The majority of the surface access costs where a split of beneficiaries is expected (for
example, where multiple businesses and the public at large benefit from a new road
junction or rail scheme) are likely to be borne by Government, as the schemes provide
greater benefits for non-airport users. The airport contribution would be subject to a
negotiation, and review by regulators.
4.31 Because of the early stage of development, there is some uncertainty about surface
access costs, which are subject to more detailed development and, for example,
choices over precise routes. The additional public expenditure effects of the options
would likely be as follows:
• For both Heathrow schemes, there is no Government road spend directly linked
to expansion. The promoter would pay for changes to the M25, A4 and A3044
and any local roads. The Western and Southern Rail schemes are at different
levels of development and, based on current estimates, could cost between
£1.4 billion and £2.5 billion together. The Government would expect this cost to
be partly offset by airport contributions, which would be negotiated when the
schemes reach an appropriate level of development.
• For the Gatwick scheme, there would be no additional public expenditure solely
because of expansion, as all road enhancement costs for airport expansion
would be met by the scheme promoter. The Government has assumed that any
improvements to the Brighton Main Line that may be required would take place
regardless of expansion and would be publically funded.