The planned Heathrow Third Runway is facing fresh questions after new government analysis suggested its economic benefits may be much smaller than earlier estimates. The review found that the project could increase the UK's gross domestic product by only up to 0.05%, far below previous forecasts of around 0.5%. The findings have added new pressure to one of the country's biggest infrastructure projects. Supporters say airport expansion will create jobs and improve trade links, while critics argue the financial, social, and environmental costs could outweigh the gains. Government documents show that the overall value of the project could be negative. Officials estimate the net present value of the runway to range between minus £23.4 billion and minus £62.5 billion. This measure compares all expected benefits with the total costs over the life of the project. The analysis says passengers could receive benefits worth between £29 billion and £42.4 billion. These gains mainly come from lower air fares, more flight choices, and wider economic activity linked to better air connections. However, those positive effects are expected to be offset by much larger costs. The assessment estimates that social and environmental impacts could reach between £58 billion and £82 billion. In addition, airlines and other airports could lose around £25 billion in profits because of changes in competition and passenger traffic. The government continues to support the project as part of its economic growth strategy. Officials believe expanding Heathrow will improve international connections and strengthen the country's position as a global business hub. Government documents say outside experts found that the project could add up to 0.05% to GDP by 2056. Earlier estimates had suggested economic growth of between 0.43% and 0.5%, making the latest figures around 90% lower than previous expectations. Some economists argue that these new numbers weaken the business case for expansion. They believe the project may not provide enough economic value to justify its high cost and possible impact on local communities. Government officials responded by saying that net present value is only one way to measure success. They argue that a larger Heathrow could support more than 60,000 local jobs and generate around £40 billion in wider benefits for the UK economy. Officials also stressed that private investors would finance the expansion rather than taxpayers. They say the project could attract international investment and improve Britain's global connectivity for decades. Heathrow also defended the proposal. Airport representatives said the government model does not include every economic advantage. They believe a larger airport would improve trade, increase business activity, and make the UK more competitive in international markets. The project is now moving to the next stage of the approval process. The government has launched a consultation before a parliamentary vote and hopes construction can begin by 2029 if the plan receives final approval. The proposed runway would stretch for 3,500 metres and require major changes to surrounding infrastructure. Plans include diverting part of the M25 motorway and demolishing about 800 homes. Once completed, the runway could add around 276,000 extra flights every year. Current estimates place the project cost at around £33 billion. However, an independent review prepared for aviation regulators suggested the final price could range between £32.7 billion and £52.4 billion. Separate government health analysis also raised concerns about the project's wider impact. The report found that up to 3 million people living near Heathrow could experience negative effects on health and wellbeing. The assessment also warned that expansion may increase pressure on housing, schools, healthcare services, transport networks, open spaces, and water quality while affecting local communities. Supporters believe the third runway will create jobs, improve travel options, and strengthen the economy. Opponents argue that the latest figures show the expected economic gains are limited and may not justify the financial, environmental, and social costs. As the approval process continues, the Heathrow Third Runway remains one of the UK's most debated infrastructure projects, with its future likely to shape the country's transport and economic strategy for many years.