David Cameron has been accused of “bottling it” after the UK Government announced it will delay its decision on airport expansion in the south-east of England.
The SNP said the prime minister had put political convenience before securing the UK’s connectivity.
Last night, Transport Secretary Patrick McLoughlin said the case for increased capacity by 2030 was clear.
But he insisted it was “vitally important” to get the decision right so it would benefit future generations.
Mr Cameron, who gave a “no ifs, no buts” promise to block a third runway at Heathrow in 2009, had promised a decision by the end of the year.
But it has now been put back so the environmental impact of the Airports Commission’s recommendation for expansion at the west London airport – and consideration of the “best possible mitigation measures” – can be carried out.
A decision on location is not now expected until next summer when the assessment is due to conclude.
The government confirmed last night, however, that it had accepted the commission’s shortlist of options, which also includes expansion at Gatwick, as “viable”.
Announcing the delay, Mr McLoughlin said: “We will undertake more work on environmental impacts, including air quality, noise and carbon.
“We must develop the best possible package of measures to mitigate the impacts on local people.”
SNP transport spokesman and Inverness MP Drew Hendry said the delay was “all about splits within the Tory party”.
He added: “We were promised a decision before the end of the year, but the prime minister has bottled it.
“The way this has been announced is also grossly discourteous to parliament and I have tabled an urgent question on the shambolic way this vital issue has been handled by the government.”
Green MP Caroline Lucas, who wants the government to consider a frequent flier levy, branded the postponement unacceptable “when a rejection (of expansion) is what’s needed”.
Scottish Secretary David Mundell is understood not to have attended last night’s meeting of the airports sub-committee, of which he is a member, due to a “full programme” in Scotland.
Its decision is due to go before the Cabinet on Tuesday.