Given the Conservatives' blanket opposition to expansion at Heathrow, Gatwick and Stansted, and their conscientiously-crafted green image, you'd be forgiven for believing that airport expansion is firmly off the table. Far from it. Airport expansion in Britain is alive and well. Campaigners won a landmark high-profile victory when they defeated the plans for a third runway at Heathrow, and it appeared environmentalists could claim a comprehensive triumph. However now, out of the media spotlight, regional airports are seizing the opportunity to grow at the expense of their more famous London rivals.

With expansion at London's largest airports out of bounds but demand for flights increasing, regional airports are clamouring to market themselves as alternatives. Southend is the latest, last month announcing a ten-year deal with easyJet to offer cheap flights to Europe. The runway is being extended to accommodate holiday jets and, from April next year, they will be flying to destinations such as Ibiza, Barcelona and Faro. The airline is moving some routes from Stansted to Southend, claiming that it will fly 800,000 passengers through the new terminal next year.

According to Plane Stupid, which campaigns against airport expansion around Britain, 20 airports around the country have similar expansion plans, suggesting a stealthy increase in the number of flights, despite the well-publicised ban on the London airports. Joe Ryle of Plane Stupid explains: 'we have had a successful five-year battle. Now we have to focus on the regional airports, but the shift away from London has made it harder to motivate the media's attention'.

So far NIMBYs in the regions outside London have been much less successful that their London counterparts. As John Stewart, a trustee of Campaign for Better Transport, commented: "The regional campaigners have far fewer people affected by noise to call on and have not made the wider alliances, which were so important at Heathrow. They are not helped by the fact that the new Government, by doing very little on aviation, has taken the heat out of the situation."

Heathrow currently acts as Britain's main hub and it's at full capacity - hence BAA's pleading for the third runway. It serves just 171 destinations, while Amsterdam's Schiphol airport flies to 222, Charles de Gaulle in Paris serves 223 and Frankfurt has 262. No full-length runway has been built in the South East of England since the 1940s. The fear is that the UK is losing out on the number of flights to our European counterparts. Many aviation leaders and even Conservative MPs believe the Tories' aviation policy is damaging to business. There are widespread fears both in the City and at Westminster that Heathrow is on the verge of losing its international hub status.

While the government prevaricates, Boris Johnson has broken ranks, vociferously championing an estuary airport on reclaimed land to fill the gap of the third runway. But logistically this could only be realised in the distant future - if ever. Some Conservatives accuse the Mayor of political opportunism in offering a solution that is extremely unlikely to ever become a reality.

More probable is growth at Gatwick, once an agreement to suspend building expires in 2019. However, Gatwick is mainly for holidaymakers and will not necessarily help business links in the way that Heathrow does.

Last year's 'Vote blue, go green' opposition to Heathrow's third runway by the Conservatives looks increasingly suspect. Coalition policy has expanded the role for regional airports - at the cost of maintaining London as a business centre and without the benefit of freezing carbon emissions. Government opposition to expansion at Heathrow, Gatwick and Stansted had little to do with carbon emissions, and everything to do with political expediency. The blocking of the third runway was a great result for NIMBYs in marginal seats and the Conservatives who pandered to them in exchange for their votes, but it has left British commerce at risk of losing ties with overseas business interest, whilst the environmentalists can claim only a flawed victory.

As Martin Rivers, an aviation commentator, points out 'the Tories made this policy a cornerstone of their election and a U-turn is now politically very difficult, despite dissent within the party and among UK businesses'. However, an incoherent policy on aviation is a concern to environmentalists and businessmen alike. Environmentalists are seeing carbon emissions set to increase on the quiet and business leaders fear that if London airports are unable to increase business flights to emerging market economies of Asia and Latin America, they will lose jobs and revenue to European competitors, as well as deterring emerging market business from setting up here.

Philip Hammond, the Transport Secretary, does not plan to enact a new aviation policy until April 2013. This means Britain will have gone without a coherent policy for over two years. Pushing flights outside London does little to help the environment and does great harm to the British economy. Even if the Government, or Boris Johnson for that matter, do find a workable approach, it's going to be a long wait.