Heathrow Airport’s proposed third runway has encountered renewed challenges following critical assessments from key figures involved in its review process. Ruth Cadbury, the Labour MP chairing the Commons transport select committee, expressed serious doubts about the project’s economic viability, describing the case for expansion as “even weaker” than it was when Parliament last debated the issue nearly a decade ago.

In remarks delivered at the Labour Party conference in Liverpool, Cadbury highlighted findings from recent scrutiny that indicate the anticipated contribution of the third runway to economic growth will fall significantly short of earlier projections. Citing Department for Transport (DfT) data from June, she noted that the runway’s expected boost to the UK’s GDP had been revised downward to a maximum of 0.05 percent—approximately 90 percent less than prior estimates. Cadbury also referenced a report from the Climate Change Committee (CCC), which concluded that expanding Heathrow is incompatible with the country’s legally binding target to achieve net zero carbon emissions by 2050.

The CCC further recommended that if the project proceeds, the Government should adopt a “polluter pays” framework, incorporating green aviation fuel costs and measures to control demand through higher fares. Cadbury conveyed concerns heard during the committee’s inquiry, including those from airlines warning that Heathrow’s proposed £65 per passenger charge to help fund the runway could prove unsustainable and may price out some carriers and travelers.

Labour figures remain divided over the project. Greater Manchester Mayor Andy Burnham declined to endorse the third runway, describing it as a “contested issue” with primary implications for London residents. Cadbury, however, refrained from predicting the committee’s forthcoming conclusions, noting that Heathrow’s chief executive, Thomas Woldbye, and other stakeholders had yet to provide evidence before the committee.

Heathrow Airport, responding to the criticism, expressed readiness to further outline how expansion might deliver essential economic growth while adhering to net zero commitments. A Government spokesperson confirmed that consultations on the Heathrow third runway blueprint remain ongoing, with a final decision anticipated next month.

At an estimated cost of £49 billion, the project’s financial scale, environmental impact, and uncertain economic advantages have become focal points in this latest evaluation phase, casting new questions on the viability of the long-debated Heathrow expansion plan.