Johnson's opposition is well known, but how did many of his peers respond?
It's not just Boris who's angry about Heathrow, his fellow cabinet member and south west London MP Justine Greening is spitting feathers too.
In a statement, Greening said she was “extremely disappointed with the decision”.
“My views against expanding Heathrow, particularly on the impact of noise and air pollution on local residents and the weak economic case, are long-held and well-known,” she said.
Greening and Johnson are the only cabinet members to be granted permission by the prime minister to publicly oppose the decision so far.
Labour's official line is pro-airport expansion, with no particular bias towards either of the airports, although you wouldn't know that from shadow chancellor John McDonnell, whose constituency includes Heathrow.
McDonnell said that building a new runway at Heathrow would be devastating for local residents.
“I'll continue to support my constituents in campaigning against this runway so that it never sees the light of day,” he said.
Goldsmith is set to make a formal announcement later today, but said in the House of Commons that a new runway was both “wrong” and “doomed” with expansion facing sufficient challenges to make it “a millstone around the government's neck”.
Goldsmith's south-west London constituency neighbour Dr Tania Mathias – whose team have previously told City A.M. she would back “whatever Zac decides to do” – was similarly aggressive, declaring expansion “misguided and not in the nation's interest”.
Terrible decision by Govt. I will continue to fight against 3rd runway at Heathrow. I am confident there will never be expansion at Heathrow— Dr Tania Mathias (@tania_mathias) October 25, 2016
But there has also been plenty of vocal support for the project among MPs, not least among those glad a decision has finally been taken.
Kwasi Kwarteng, whose Orpington constituents include many workers at Heathrow said his only regret was that the government was not backing additional construction at Gatwick and Stansted.
"We should be having three more runways," he said.
"We have got to face up to the fact that there is a whole world of opportunity in trade and tourism and in order to grow we have to accept that we probably need a bit more capacity."
MPs will be granted a vote on the new runway in winter 2017/18. Foreign affairs committee chair - and Heathrow supporter - Crispin Blunt has previously said he expected the House of Commons to back expansion by "a substantial majority".