Return of the eco-warrior

If you were lucky enough to jet off on a summer holiday this year, it is highly likely that you travelled to your exotic destination by aeroplane. In fact the number of people taking advantage of ever cheaper flights is growing at such a rate that there are expected to be more than 500 million air passengers by 2030 - up from 180 million in 1998. To cope with this rise in demand, the government intends to expand Britain's airports' capacity by nearly 300%.

The plan is simple: a white paper will be released in the next three months identifying the best sites for development; airport operators and construction firms will then secure planning permission; and building will get under way. But actually getting those new runways built could turn out to be far from simple Developers face opposition from locals, and the hardcore road protesters of the early and mid-1990s - remember Swampy? - are stirring again, threatening to switch their attention to aviation.

Former eco-warrior Stig, a veteran of the Newbury bypass and Manchester runway protests, says the airport extensions could bring her cohorts out of retirement. "Aeroplanes are so much more polluting than roads," she says. "The obvious next step [for environmental campaigners] is to combat air travel. There are so many cheap flights now and everyone is flying everywhere. Lots of the former protesters are living in communes and doing political campaigns at a local level. But if they had a cause, they'd go back on site – they're still active. They haven't gone away."

In fact, the movement is already beginning to build again, according to anti-roads campaigners at the RoadWatch website: "Things are really moving again – there was a great action on the site of the Birmingham Northern Relief Road a few months ago when the original Twyford Down people occupied it, that really kicked the movement back into action. I'm sure the airports issue will bring new supporters into the movement, too."

Stig also emphasises that it is not just experienced campaigners who are up for the fight. "Hopefully this [airport expansion] will attract a new generation of protesters living on sites," she says. "The construction of Manchester Airport's second runway in 1997 caused huge protests. These new plans are so much bigger, it's bound to attract much more opposition. It's going to cause a big storm, definitely." And whereas anti-road protests could sometimes be calmed by re-routing a stretch away from controversial sites, there is little chance of this with new runways, she adds. "The old protests were partly anti-car, but they were also about the trashing of that particular bit of land. But the Manchester protest was simply about the fact that it was going to be a new runway."

There have not been any significant protests yet, but could this be the calm before the storm? A spokesperson for the Civil Engineering Contractors Association says construction companies haven't yet noticed disruption to their work from protesters, but he remains cautious. "Our members aren't concerned about it yet. It's quiet at the moment but it could spring up very possibly anywhere. In the 1990s it was a massive inconvenience – it's impossible to say how much delays could cost." A few committed activists would be able to delay work for weeks, he emphasises. "It only takes one Swampy to hold up a whole road – by tunnelling, for example. That's the most difficult protest technique to deal with."

And it seems that his caution is warranted. According to anti-airports campaigner Rowan, protesters could move onto threatened sites as early as Christmas. "An announcement as to which sites have pulled the short straw is expected towards the end of the year," she says. "That's when the protest camps will be set up - there's just not enough people to go round all the threatened sites at the moment, so it will have to wait until we know which ones definitely need fighting."

So what can construction companies do to minimise the hassle they may face from protesters? Pre-empt the problem with plenty of local liaison work before you move in, suggests Balfour Beatty. "We would do an environmental impact study as a matter of course; we also undertake consultation with the local community; and we now appoint community liaison officers," a spokesperson says. "You can try to secure your site against protesters, but we'd aim to avoid that situation arising in the first place."

However, if it is too late to implement such measures and the project is already facing well-organised and determined environmentalists, your main aim should be securing the site.

"The level of security you need will depend on the level of the threat, so get as much information as possible about the protesters beforehand. It's impractical to fence the whole of a long thin site like a road scheme, but you should have a visible security presence at certain key points, which will discourage them."

In the mid-1990s, contractors began to tackle controversial schemes in sections – clearing one section of protesters while building on another recently cleared area. This is one way of mitigating expensive delays. Another way is to collect intelligence on protesters, a contractor who did not wish to be named told Building. The client will have been aware of protesters' presence on the site for a long time and should be able to help. And obviously your own security has a vital role to play. "Security must alert the project team to the threat of protesters before they become encamped, because then they start to acquire legal rights and it's a lot harder to get rid of them," says Balfour Beatty's spokesperson. Specifically, once treehouses are in place protesters can claim legal residence on the site; treehouses have been officially recognised as dwellings since 1993, making it much harder to be evicted.

In the 1990s, environmental protests were a massive inconvenience – it’s impossible to put a cost on delays

Civil Engineering Contractors’ Association spokesperson

Security must alert the team to the threat of protesters before they are encamped, then they start to acquire legal rights

Balfour Beatty spokesperson