By Brian Wheeler
BBC News politics reporter
What is the best way of drawing attention to a problem? Writing a letter to your MP - or throwing a custard pie in their face?
So-called "direct action" protests have taken off in the UK in recent years, with groups from Fathers4justice to the Countryside Alliance grabbing headlines with eye-catching stunts, disrupting of public meetings and even invading the House of Commons.
But do such protests actually achieve anything? And what do they mean for democracy?
Campaigners against airport expansion are, it seems, the latest group to consider turning to direct action.
Frustrated by years of public inquiries and court cases which always seem to go against them, some residents in the Heathrow area are even believed to be seeking out training in how to stage effective non-violent protests.
The hurling last month of a custard pie at transport secretary Alistair Darling, at a conference in London, could mark a tactical turning point, according to Heathrow anti-noise campaign group HACAN Clear Skies.
"As an organisation, HACAN can not recommend direct action but I think you will be seeing more of the kind of event where Alistair Darling was pied with the cake.
"People will take that sort of action more regularly," says HACAN's chairman John Stewart.
"I think our members feel they have done everything they can through the conventional campaigning process."
This new approach has been made possible, he argues, by the Countryside Alliance, which has made "direct action fairly acceptable to people who would consider themselves law-abiding".
"The middle classes, Middle England, if you like, look at the Countryside Alliance and say these are people like me.
"There is always a huge barrier for people, particularly if it is illegal, which most of this sort of action is.
"Getting over that barrier is an enormous thing, but when they see people like the Countryside Alliance and Fathers4Justice then it becomes easier."
Rebecca Lush, the woman who hurled the pie at Mr Darling - it was in fact a Marks and Spencer creamy carrot cake, she points out - is a veteran of environmental protests around the country and was jailed for four months in 1993 for her part in protests at Twyford Down.
She says she was incensed by the presence of Mr Darling at the launch of Future Heathrow, an air industry lobby group.
"I was absolutely appalled. Why have a campaign group when you have already got the minister on your side?"
She gained entry to the event at CBI headquarters in London by posing as a journalist, with her carrot cake concealed in her lunchbox.
After throwing the cake at Mr Darling she managed to shout: "Future Heathrow stinks. Your bogus economic arguments stink. Alistair Darling being here stinks. And your vision for the planet stinks," before being bundled out of the room by security.
'Dramatising the situation'
The stunt received some coverage in the national press but lost much of its impact because no press photographers or TV cameras were present.
So what did she achieve?
"Nobody would have known that Alistair Darling was sat there on a platform with a group that are going to make the lives of residents hell."
She says direct action can "dramatise the situation".
"It adds drama to issues that might not get coverage otherwise. It sheds lights on issues, exposing sleaze and corruption."
Local residents protesting outside the meeting were so impressed with the stunt they have asked her to arrange "direct action" training, she says.
Will that include lessons in how to throw pies at ministers?
"If they want to do that kind of thing."
Ms Lush says people no longer trust the "normal procedures" because they see things "getting done for economic expediency, not because they are right and just".
She cites Clive, now Lord, Soley, the former West London Labour MP, who now runs Future Heathrow, as an example of the "cynicism" that is infecting modern politics.
"He is someone who was supposed to be looking after his constituents' interests, who is now going completely against their interests."
Not surprisingly, Lord Soley, who invited Mr Darling to speak at the Future Heathrow meeting and attempted to shield him from the flying carrot cake, rejects this analysis entirely.
He says he lives under the Heathrow flight path himself and far from betraying the interests of his former constituents he has consistently spoken out in favour of Heathrow expansion - the "only West London MP" to have done so.
He believes there is a genuine threat to the future of the airport if it is not allowed to expand, with the possible loss, in the long run, of 70,000 jobs.
He says he understands how protesters might feel "outgunned" by the involvement of himself and Mr Darling and the recent appointment of former British Airways chief Rod Eddington to advise the government on aviation policy.
But all Mr Darling was doing at the Future Heathrow launch was setting out the government's position, which is articulated in their white paper on civil aviation, and includes the possibility that expansion could be limited by environmental concerns.
What is more, Lord Soley argues, Future Heathrow has the backing of the trade unions, in addition to the aviation industry, both of whom know that increasing airport capacity is crucial for the prosperity of the UK.
The danger with "direct action", as opposed to more conventional means of protest, is that it can be undemocratic, he argues.
"They don't know if they are a majority. They may actually be a minority," he says, of protesters like Ms Lush.
The danger is that the people who make the loudest noise will get their way, regardless of the strength of their argument.
"What gives her the right to use direct action to overwhelm everybody else? Nobody knows whether there is a majority for or against airport expansion," Lord Soley says.
Conservative MP for Uxbridge, John Randall, who last week led a Westminster Hall debate on airport expansion, says he is not surprised some Heathrow protesters are considering a more militant approach.
"I would never encourage anything that was against the law but I do understand that to get your point across these days you have to make a lot of noise."
The majority of his constituents are against expansion, he says, and they are angry that their views are not being taken into account. He also feels angry and "frustrated".
"I wouldn't preclude myself from becoming Swampy at some stage," says Mr Randall, referring to the well-known environmental campaigner.
"But you have to be careful. You can lose public sympathy just as easily as you can gain it. Our job as Parliamentarians is to pursue the lines open to us."
He said he has high hopes new air minister Karen Buck will prove more receptive to residents' concerns than her predecessor.
But, he adds, the government is "very good at going through the motions" of consultation and listening to the public and that "people are right to be cynical".
So are MPs simply wasting their time in lobbying ministers on behalf of their constituents?
"The fact that I am still doing it means I must have some faith in it," he says.
Here are some of your comments:
It is not justified in a democratic society - ever.
When government policy is largely determined by column inches in the major newspapers, what better way to have your influence on government policy than to do something that generates newspaper attention. Bit of a no brainer really!
Michael Shaw, Sheffield, UK
Without direct action women wouldn't have the vote. Without direct action segregation would still be enforced in the US. Without direct (industrial)action children would still be sent up chimneys and down mines. Direct action is the real democratic tradition - more so than the spun, lobbied, compromised business of electoral politics. Join a union, get active in a campaign, make your voice heard.
Ben Drake, York, UK
It very much depends on the impact of the action. For instance I have often believed that the train service could do with a series of one-day 'payment strikes' by passengers, where passengers refuse to pay for services but still use them. Such action would not cause harm to anyone but would financially inconvenience those responsible for services. However, this type of action is only effective in large numbers.
Tony Lacey, Manchester, UK
I have very little sympathy for folks who chose to live near Heathrow. There can be very few folks still there who lived in the area before the airport opened. Could they not see that traffic volumes at London's first major airport would increase in time. Most could live else where. I'd bet they'd also complain if they couldn't fly to Spain on holiday. (This is much the same as the whingers who moan about cell phone masts, then withdraw their phone from their pocket when it rings.) It's time for these Luddites to get a life. It certainly isn't time for them to moan and whinge.
Dougie Lawson, Basingstoke, UK
I've recently been involved in direct action against a bypass. We haven't persuaded the council not to build it, but we have obtained valuable concessions including traffic calming and improvements to public transport. Before our direct action began the council refused to consider the same measures they're now implementing. Direct action can achieve change.
Sean Kelly, Wing, Bucks
'"Nobody knows whether there is a majority for or against airport expansion," Lord Soley says." Well find out then before you plough on! Direct action has sprung up precisely because those in power don't listen and find out. Democracy is about debate - and those in power seem to only want debate that supports them. Upon launching all these grand schemes the government should be consulting affected people and finding out! Until they do, direct action is the only way that people can be heard or raise an issue to get a debate going!
Paul, Cardiff, UK
When does direct action become terrorism? States that deny a large minority a voice can only expect this type of action. What would the world think if the government of Hitler had not been challenged. Complicity in atrocities happen because people are scared to take action.
John Smith, Leeds England
Direct action can never be justified. We live under the rule of law - it is by due process of law that matters must be resolved.
Mel Quick, Arundel, UK
Those who take "direct action" should be prepared to accept "direct action" in return. Throw an egg at John Prescott and he'll respond equally "directly". Throw a custard pie at George Bush and see how many times his bodyguards shoot you. In most cases the ends do not justify the means.