IT was South Suffolk MP Tim Yeo who lit the fuse on a row that has now led to the removal of a cabinet minister and sparked furious rows at the top of Government.

The debate over the south-east’s air capacity and what to do about it has long been a toxic topic – and it threatens to remain that way.

Prime Minister David Cameron is expected to announce economist Sir Howard Davies will head an inquiry into what Britain should do to address the issue in the coming days.

And any investigation will have to look not only at Heathrow and the so-called “Boris Island” plan but Essex’s Stansted as well.

As the row once again gathered pace, Ryanair boss Michael O’Leary switched the focus back to Stansted saying he believed the next runway in the south-east would be built there. He added that he also thought Heathrow and Gatwick would get extra runways in the fullness of time.

Concerns over airport capacities have been on the agenda for years. In the 1970s, Edward Heath’s government proposed building an airport at Maplin Sands off Foulness, in south Essex – a similar project to London Mayor Boris Johnson’s plans for terminals and runways in the Thames Estuary.

Any expansion of the airport would affect a huge number of people over a wide area – and would affect both marginal constituencies in west London and safe Conservative seats in the prosperous Thames valley.

Opposition to a third runway at Heathrow was a specific point in the coalition agreement signed in May 2010.

Last month, Mr Yeo called for the proposal to be revisited and asked whether the Prime Minister was “man or mouse” over the issue.

Transport Secretary Justine Greening – who represents the marginal west London seat of Putney – said she would not agree to an expansion of Heathrow, while Richmond Park MP Zac Goldsmith said he would not stand for the Tories again if their position changed.

For years the major debate on airport expansion focused on Stansted. And now many business leaders think Stansted could take the weight off other crowded airports by making use of the full capacity – but airlines and passengers would need convincing it is a viable option.

Campaigners saw off a proposal to build a second runway when the issue was last in the spotlight. Carole Barbone, from the Stop Stansted Expansion group, said: “The attention now seems to be on the development of a new ‘hub’ airport with many runways and that is not what has ever been proposed at Stansted – and there would never be the possibility of that happening.

“Stansted already has permission to operate at a capacity of 35million passengers a year but at present is only operating at 17m.

“There is a long way to go before it reaches capacity.

“And it is clear that major international airlines don’t want to go to Stansted – they don’t think it has good enough facilities and it remains an airport for short-haul leisure flights.”

But Essex and Suffolk’s business communities would welcome more international and long-haul flights at Stansted and have urged airlines to take advantage of the airport’s capacity.

Meanwhile, the row over Heathrow rumbles on – despite the Prime Minister attempting to put off any decision until after the next General Election which is scheduled for 2015.

Yesterday Mr Yeo – who is championing Heathrow expansion rather than any changes at Stansted – said: “The business community now is almost unanimous in saying this is an urgent issue. We need more runway capacity in the south-east in the 2020s, not in the 2030s.

“We’ve made a very good start actually by moving Justine Greening, who was a good Transport Secretary but had a difficult constituency issue to address.

“If we made this decision now, it would send a really encouraging signal to all those people who are investing here.”

In the Commons Mr Cameron said: “Let me be very frank about this – very large infrastructure projects are extremely difficult for individual governments to take and to deliver.

“What we need to do is build a process that hopefully has cross-party support, so we can look carefully at this issue and deliver changes that will address the problems of capacity we will have in future years, and address the issue of the hub status of the UK.

“I think it’s important we work across party lines because this won’t happen unless parties sign up to a process they can deliver.”