Question to the Department for Transport:

To ask the Secretary of State for Transport, with reference to paragraph 8.18 of the Airports Commission Final Report, July 2015, what the estimated cost is of the tunnelling work required for the M25; and whether that cost would be incurred by the public purse or Heathrow Airport Limited.

Alongside its Final Report in July 2015, the Airports Commission published a range of supporting analysis and assessments. The Cost and Commercial Viability: Financial Modelling Input Costs Update report included estimated costs for the surface access proposals for each of the Commission’s three short-listed options for airport expansion.

The report set out the estimated capital expenditure costs for the works associated with M25 tunnelling (south of junction 15) as £576m for the Heathrow Airport North West runway option and £864m for the Heathrow Airport Extended Northern runway option.

The Airports Commission made clear in its Final Report (paragraph 16.33) that Government would need to agree the nature, scale and financing of the surface access transport improvements associated with expansion, and the Government has been clear that it expects the scheme promoter to meet the costs of any surface access proposals that are required as a direct result of airport expansion and from which they will directly benefit.