Plans to build a third runway at Heathrow Airport are expected to be delayed by approximately four years, pushing its anticipated opening from 2035 to 2039. Airport officials informed government ministers that meeting the original deadline for the £49 billion project is not feasible, with a focus now on securing planning permission by 2029. Once permission is granted, Heathrow representatives said the runway would take about a decade to complete.

The expansion, first seriously considered as early as 1946, has been a contentious issue for decades. While Heathrow remains the busiest two-runway airport globally, it has been surpassed this year by Istanbul as the busiest airport in Europe. Comparisons with international counterparts highlight Heathrow’s relative stagnation; for example, Beijing Daxing International was constructed with four runways within five years, and Dubai is currently planning an airport with five runways capable of processing around 260 million passengers annually.

Supporters of the Heathrow expansion, including former Chancellor Rachel Reeves, have emphasized potential economic benefits, such as creating 100,000 jobs and stimulating growth across supply chains in manufacturing and services. Reeves had targeted a 2035 operational date when the government voiced formal backing for the project last year. However, some voices within the Labour Party, including Ed Miliband and London Mayor Sadiq Khan, have expressed opposition or reservations about the plan. Prime Minister Sir Keir Starmer, who previously held reservations while serving as Mayor of Greater Manchester, is now reportedly more open-minded about the expansion, viewing it as a potential driver of economic growth.

The project faces several obstacles beyond timing. A notable dispute has arisen between Heathrow and billionaire landowner Surinder Arora, who has proposed an alternative scheme for the runway that would avoid moving the nearby M25 motorway by constructing a shorter landing strip. Following a public consultation on the Heathrow Expansion National Policy Statement earlier this year, officials are reviewing feedback before finalizing the policy, which will then be subject to a parliamentary vote. The vote, initially expected this autumn, may now be delayed until January. If approved, multiple parties, including Arora, could submit competing planning applications, with the transport secretary ultimately deciding which proposal to approve.

Environmental groups are anticipated to challenge the expansion in court, a familiar hurdle for large infrastructure projects in the UK. Critics argue that political delays, regulatory complexity, and legal challenges have hindered airport and major infrastructure developments for years, contributing to Britain lagging behind other countries such as France and China in transportation capacity and efficiency.

Despite these setbacks, union representatives like Gary Smith of the GMB describe the revised timeline as practical and achievable. Still, some policymakers caution that delays could undermine broader efforts to boost economic growth. As the Labour Party convenes for its annual conference, there are calls from within the party to accelerate action on infrastructure to better align with economic ambitions and public needs. The Department for Transport has acknowledged the original timeline’s ambitious nature and pledged ongoing collaboration with Heathrow and other stakeholders to establish a suitable framework for progressing the third runway application.