A third runway for Heathrow is back in the offing as the chancellor has backed expansion of Europe’s busiest airport.
This is not the first time an extra runway has been proposed, with Heathrow’s expansion having a chequered past.
The first plans for Heathrow had six runways in a hexagon shape (pictured below), with a proposal for three more to be added.
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It was initially built with those six runways in 1946 but by the 1970s three had been closed due to new planes needing longer runways.
A fourth was decommissioned in 2003, leaving the two current runways.
Discussions about a third parallel runway began in the 1980s and in 2009 Gordon Brown’s Labour government approved an expansion, saying it was needed for economic reasons.
The Conservative-Liberal Democrat coalition scrapped it in 2010, with then prime minister David Cameron saying there would be no expansion “no ifs, no buts”.
Mr Cameron’s government established the independent Airports Commission to look at London’s airport capacity problems and in 2015 it recommended Heathrow as the preferred site for a new runway.
In 2018, Theresa May’s government approved the plan but it was opposed by several local MPs, including Boris Johnson who said he would lie down in front of bulldozers to stop its construction.
However, Mr Johnson, then foreign secretary, was not there for the vote as he was in Afghanistan.
Sir Keir Starmer, current Net Zero Secretary Ed Miliband, Culture Secretary Lisa Nandy, Environment Secretary Steve Reed and Northern Ireland Secretary Hilary Benn also voted against the plans at the time.
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In early 2020, London Mayor Sadiq Khan, city councils and environmental groups applied for a judicial review against the plans.
The Court of Appeal ruled the expansion decision was unlawful as it did not take climate commitments into account.
However, later that year the ruling was overturned by the Supreme Court after Heathrow appealed it, allowing a planning application to go ahead.
The plan was stalled by the pandemic and falling passenger numbers post-COVID, as well as concerns about cost.
In 2024, Heathrow’s boss said building a third runway is “still part of the strategy” for coping with ever-increasing passenger traffic at Europe’s busiest airport.
Last year, the airport broke its record for the highest number of passengers, with 83.9 million using Heathrow in 2024 – three million more than its previous record in 2019.
It is consistently in the world’s top five busiest air hubs and is forecast to serve 84.2m passengers this year.
