The decision to back a third runway at Heathrow has "stood the test of time" despite the recession, the transport secretary has said.
Lord Adonis added he was confident that a "satisfactory position" could be reached with the European Commission on pollution levels at the airport, which currently exceed acceptable limits.
And he said that nitrogen dioxide emissions from aircraft and road vehicles are expected to halve by 2030 compared to 2002 even with a fully utilised third runway.
During questions in the Lords on Monday, Conservative peer Lord Trefgarne asked whether the third runway could still be justified "in the light of things that have happened" since the government made its announcement last January.
Lord Adonis responded that he had been satisfied with the consultation that had been conducted.
He told peers: "In respect of the decision to allow a planning application to come forward for a third runway, subject to conditions being met, that decision has stood the test of time.
"Despite two years of recession, Heathrow is still running at nearly 100 per cent capacity despite the downturn in business at other airports.
"It is our main international hub airport, the lifeblood of our economy depends upon it and this government will not betray the national interest by refusing to take a decision that is manifestly in the best interests of the country."
Last month the London Assembly's environment committee concluded that there were "clear inadequacies" in the safeguards against air, noise and climate pollution imposed on the proposed expansion.

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