Britain’s economic recovery was being undermined by continuing delays in deciding how to expand the country’s airport capacity, two former trade ministers warned the Government on Sunday.

They said more than 20 cities in rapidly growing foreign markets were served by daily flights from other European cities but not London – and raised fears that Britain would miss out both in exports and attracting inward investment.

The warning from Lord Digby Jones and Lord Mervyn Davies reflects growing impatience among business chiefs with the impasse over where to build a new runway to relieve the huge pressure on airports in the South-east.

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The Government appointed Sir Howard Davies, the former chairman of the Financial Services Authority, to examine the options but he is not due to publish his full recommendations until the summer of 2015 – after the general election.

Among the schemes he is considering are a third runway at Heathrow, the alternative preferred by many senior politicians; expanding Gatwick or Stansted; and building an entirely new airport in the Thames Estuary. On the most optimistic timescale, the earliest date that a new runway could be opened in the South-east is 2023.

The two peers expressed their frustration over the delays in a letter to Sir Howard, which was copied to the Transport Secretary, Patrick McLoughlin. It was also signed by Andrew Cahn, a former head of UK Trade and Investment, the Government office in charge of boosting exports.

“We are increasingly concerned about the gradual decline in Britain’s global aviation capacity when compared with our European competitors and the negative impact this is already having on our economic competitiveness,” they wrote. “For British business to flourish in a global economy, we need to export goods and services and we need to attract inward investment to and from new, as well as existing, markets. In neither respect can we do so if our airport system is not optimised.

“While the UK has continued to do nothing, many of our developed economy global competitors such as Germany have already modernised their airport infrastructure; whilst the speed of infrastructure modernisation among emerging economy global competitors such as China is phenomenal.”

Brazil, Russia, China, Mexico, Indonesia and South Korea are among the fast-growing economies to which London’s airports lag behind rivals such as Paris, Frankfurt and Amsterdam in numbers of flights.

The former ministers urge Sir Howard to ensure his interim report, to be published in December, is “robust and bold” in making recommendations for boosting aviation capacity in the short term.

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The Coalition is suspected of setting a post-election deadline for Sir Howard’s full report because of the number of marginal seats in South-west London which would be affected by additional flights to Heathrow.

Vying for take-off: the five options

A third runway at Heathrow Possible sites have been identified to the north, north-west and south-west of the existing airport – already one of the world’s busiest.

A second runway at Gatwick This would be built to south of the airport and could, it is claimed, treble passenger numbers.

Expanding Stansted The development of a £10bn “hub” at the Essex airport with four runways, from one at present.

“Boris Island” The construction of an artificial island in the Thames Estuary. Enthusiastically promoted by London Mayor Boris Johnson, hence its nickname.

Isle of Grain Building a £24bn four-runway international airport across hundreds of acres of rural Kent.

Poll: We want more London flights

According to a poll commissioned by the business organisation London First, the public supports an increase in numbers of flights in and out of the capital by a margin of three to one.

The YouGov survey found 43 per cent wanted more flights, with 14 per cent opposed. Almost two-thirds backed public transport improvements to airports that have room to grow such as Gatwick and Stansted.

London First’s chief executive, Baroness Jo Valentine, said ministers needed to be “ready to end the half-century of dithering that has plagued this issue and commit to swift action”.