Shadow Chancellor John McDonnell has praised Zac Goldsmith for his “honourable” decision to resign from Parliament following yesterday’s announcement that Heathrow airport would be given the go-ahead for expansion.

McDonnell has made the unusual decision to praise the now-former Tory MP, whose campaign for London mayor provoked controversy for use of ‘race politics’ against Sadiq Khan, saying on BBC Radio London: “Zac is a principled person. He’s done it because he’s fulfilling the promise he gave to his constituents and that’s an honourable thing to do.”

The issue affects McDonnell’s own Hayes and Harlington constituency, and he pointed to the need to work with his local council, as well as anti-third runway Mayor Khan, in defeating the proposals.

“My local authority is Hillingdon Council which is a Conservative controlled council, so it’s not my political persuasion but they will be joining with the other local authorities in a legal challenge and I’m hoping that Sadiq will as well. I think, like we did last time, I think we’ll defeat this project in the courts.”

Goldsmith will stand as an independent in the by-election triggered by his resignation. The Conservatives will not be standing a candidate against him, and the Richmond Park seat was until 2010 a Liberal Democrat seat.

McDonnell said yesterday in response to the government’s plans: “4,000 homes face the prospect of either being demolished or rendered unliveable by air pollution and noise… I’ll continue to support my constituents in campaigning against this runway so that it never sees the light of day.”

Other Labour figures have been supportive of the plans however, with the shadow Transport Secretary Andy McDonald giving a caution welcome the news, saying that airport expansion is “much needed in terms of investment and growth in our country”.

The trade union GMB highlighted that “this not only protects the 80,000 jobs directly employed at the airport but will increase to a further 114,000 jobs” adding “the project is set to have a huge impact on the UK steel sector and will create thousands of jobs in both construction and steel industries.”