Heathrow's Third Runway Would Cost Britain More Than It Gains, Government's Own Figures Suggest

A proposed third runway at Heathrow Airport would carry costs of between £23.4bn and £62.5bn, according to figures from the UK's Department for Transport cited in a Guardian opinion column by George Monbiot.

The column notes that former Chancellor Rachel Reeves had claimed the project would add 0.43% to GDP, a figure she said came from a report commissioned by the airport itself. The Department for Transport's own analysis, by contrast, put the real GDP gain at between 0.03% and 0.05% — eight to fourteen times smaller than the figure previously cited by ministers.

The transport department's assessment also weighed the project's social and environmental costs, concluding that the runway would cause significant harm to the health and wellbeing of up to 3 million people living near the airport, the column states.

The piece argues that successive governments have for decades framed airport expansion as essential to economic growth, while the underlying data points to a far more limited financial upside once broader costs are factored in.

The column calls on Greater Manchester mayor Andy Burnham to oppose the expansion, framing the decision as a test of whether policymakers will prioritize long-term wellbeing over short-term growth projections.