The chair of the National Infrastructure Commission warned today that Heathrow's competitiveness is at stake if stalling on expansion continues, as its European rivals fly ahead on connections to the likes of China.
Lord Adonis told a Treasury Select Committee hearing today discussing the state of UK infrastructure: "International connectivity which we're losing from the UK as a result of not expanding Heathrow is not, unfortunately, going to Gatwick or to Stansted or to Manchester or to Edinburgh.
"It is going to Schiphol, to Frankfurt, to Charles de Gaulle, who are getting direct connectivity with emerging markets that we're not."
"At the moment, Heathrow serves four destinations in China, Schiphol serves nine destinations in China, Charles de Gaulle serves seven and Frankfurt serves five," Lord Adonis outlined. "Now that is a terrible indictment of connectivity of UK plc."
He stressed that Amsterdam's Schiphol airport is in a country "the fraction of the size of the UK", yet has direct connections with more than twice as many Chinese destinations as Heathrow.
Heathrow was toppled from its position as the number one airport in Europe for direct connectivity earlier this year, according to a report from the Airports Council International Europe, with Schiphol flying ahead.
Lord Adonis noted that Schiphol has six runways, Charles de Gaulle has four, and during his tenure as transport secretary through 2009 to 2010, he attended the opening of the fourth runway in Frankfurt.
"We have not opened a new runway in the south east of England since the Second World War," he added.
Meanwhile the NIC's deputy chair Sir John Armitt, a member of the Airports Commission that previously recommended Heathrow's third runway as the best of the expansion options available, said the delays on the decision was "a political failure".
"The longer we delay, the more we are frankly just a laughing stock around the world," he said. "And certainly we're not going to be prepared post-Brexit to play our part."
Armitt said lagging on Heathrow was "the clearest way" to demonstrate the UK is not open to the world, echoing comments made by the London airport's boss John Holland-Kaye, who has said Heathrow expansion will signal Britain is open for business.
Last month, transport secretary Chris Grayling said he was "very confident" the government will secure a majority in parliament to deliver Heathrow expansion when the national policy statement goes before the House of Commons for a vote in the first half of next year.