Heathrow’s expansion plans were left up in the air when opponents won a Court of Appeal challenge in February.
Supreme Court judges will deliver their ruling on the airport’s appeal on Wednesday.
This will be the latest twist in a saga that began 17 years ago.
December 2003: A Government White Paper recommends a third runway is built at Heathrow.

November 2007: The Government publishes expansion plans. It says the new runway could be in operation by 2020.
November 2008: London mayor Boris Johnson, an opponent of Heathrow expansion, orders a feasibility study for an alternative plan for a new airport on an artificial island in the Thames estuary.
January 2009: Prime Minister Gordon Brown backs a third Heathrow runway despite strong opposition from local residents, environmental groups, neighbouring councils and Labour backbenchers.

October 2009: Opposition leader David Cameron tells a public meeting in Richmond, south-west London, that expansion of the nearby airport will not go ahead, saying “no ifs, no buts”.
May 2010: Labour loses the general election. The new coalition government of Conservatives and Liberal Democrats immediately scraps the third runway proposal.
March 2012: Supporters of the plan are given renewed hope when Mr Cameron and Chancellor George Osborne say there is a need for airport expansion in south-east England.
September 2012: An independent commission on future airport policy is set up by Whitehall, chaired by Sir Howard Davies.
July 2015: The commission, which dismissed the “Boris island” plan, recommends a new runway should be built at Heathrow rather than Gatwick.
Howard Davies discusses the Airports Commission decision to recommend Heathrow Northwest Runway https://t.co/8xFHr3V2uu
— UKAirportsCommission (@ukairportscomm) July 1, 2015
June 2018: MPs vote in favour of expansion by a large majority.
February 2020: Campaigners win a Court of Appeal ruling over the third runway on environmental grounds. Heathrow Airport says it will appeal to the Supreme Court.
October 2020: A panel of five Supreme Court justices hear the challenge.
December 2020: The judges deliver their ruling.
(function(i,s,o,g,r,a,m){i[‘GoogleAnalyticsObject’]=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,’script’,’//www.google-analytics.com/analytics.js’,’ga’);
ga(‘create’, ‘UA-72310761-1’, ‘auto’, {‘name’: ‘pacontentapi’});
ga(‘pacontentapi.set’, ‘referrer’, location.origin);
ga(‘pacontentapi.set’, ‘dimension1’, ‘By Neil Lancefield, Press Association Transport Correspondent’);
ga(‘pacontentapi.set’, ‘dimension2’, ‘94541ffd-7f3e-46a4-8c76-928f539c6987’);
ga(‘pacontentapi.set’, ‘dimension3’, ‘paservice:finance,paservice:finance:city,paservice:news,paservice:news:uk’);
ga(‘pacontentapi.set’, ‘dimension6’, ‘story’);
ga(‘pacontentapi.set’, ‘dimension7’, ‘composite’);
ga(‘pacontentapi.set’, ‘dimension8’, null);
ga(‘pacontentapi.set’, ‘dimension9’, null);
ga(‘pacontentapi.set’, ‘anonymizeIp’, true);
ga(‘pacontentapi.send’, ‘pageview’, { ‘location’: location.href, ‘page’: (location.pathname + location.search + location.hash), ‘title’: ‘Latest twist in Heathrow expansion saga’});