Image copyright Getty Images The government has approved a third runway at Heathrow to expand UK airport capacity.
Ministers approved the long-awaited decision at a cabinet committee meeting on Tuesday.
Transport Secretary Chris Grayling called the decision "truly momentous" and said expansion would improve the UK's connections with the rest of the world and support trade and jobs.
He will make a statement to the House of Commons about 13:00.
Both unions and business groups welcomed the decision to expand Heathrow. TUC general secretary Frances O'Grady said it was "absolutely vital for Britain", while CBI chief Paul Drechsler said it would create jobs and boost economic growth.
Heathrow management said the airport was ready to deliver a third runway that was "fair, affordable and secures the benefits of expansion for the whole of the UK".
However, Sadiq Khan, the mayor of London, said it was the wrong decision for both London and the UK.
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Expanding airport capacity in the South East of England has been a political hot potato for many years.
Although Heathrow has always been the favourite among businesses, it has attracted the most opposition from MPs with constituencies near the airport or under flight paths.
Zac Goldsmith, the Tory MP for Richmond Park who has threatened to resign if Heathrow expansion was approved, called the announcement "catastrophic" and said he would meet his constituents before making a statement later on Tuesday.
Foreign Secretary Boris Johnson and Education Secretary Justine Greening also have been vocal critics of Heathrow expansion.
Ms Greening is expected to give her reaction to the decision in a message to her constituents in Putney, south-west London, while Mr Johnson will also make a statement.
Analysis: Simon Jack, business editor
We have a long way to go before the we see the proverbial shovels in the ground - there will be legal and planning challenges aplenty to come. However, with today's decision to recommend a third runway, this government has arrived at a point its predecessors failed to. From beating ourselves up for not being to build anything, the UK is suddenly building everything.
Heathrow was chosen because of the extra boost it gives to the UK economy, but it is not the only mammoth project out there. After a last-minute wobble, the £14bn Hinkley Point nuclear power station was given the green light, while and the biggest project of them all is coming down the track fast.
Construction on the £42bn HS2 is scheduled to begin next year - and that is probably not all. Chancellor Philip Hammond has hinted he may reveal some moderate borrowing to fund targeted infrastructure spending in his Autumn Statement next month. It's enough to make the Victorians sit up and take notice.
If projections for a fairly sharp post-Brexit slowdown in the economy next year are correct then we may need this spending boost. If these projects proceed on time, there is something else we will need: people to build all this stuff. With unemployment close to historic lows, it's not clear we have enough. Like the Victorians did, it seems very likely we will need to look abroad to find the workers for our golden age of infrastructure - and that, post-Brexit, will present a political rather than an engineering challenge.
Last week, Prime Minister Theresa May moved to head off possible Cabinet resignations by giving ministers some freedom to speak out against the decision.
A study last year, led by Sir Howard Davies, recommended a third runway at Heathrow, but other options included a new runway at Gatwick or extending one of Heathrow's existing runways.
Proposed Flight Paths
Current Flight Paths
A public consultation will now be held on the effects of airport expansion before the government makes a final decision as part of a national policy statement on aviation.
MPs will then vote on that decision in the winter of 2017-18. It is unlikely that any new runway capacity would be operational before 2025.
Construction is not likely to begin until 2020 or 2021, the Airports Commission has said.
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