Steer report – Initial technical and cost efficiency assessment of capex expansion plans for Heathrow Airport

In 2025, the CAA commissioned Steer to conduct an initial technical and cost efficiency assessment of the capital expenditure expansion plans for Heathrow airport. This independent assessment conducted for the CAA suggests recommendations for further development of the proposals to help ensure the plans are feasible, operational, deliverable in a timely manner and cost efficient. It is also designed to help inform the CAA’s work on early costs and its judgement on whether proposals are credible and appropriately mature.

This document has been published alongside our Draft Decision on the regulatory treatment of early costs of capacity expansion at Heathrow airport.