The activists have established a complex communication system via GreenNet, a network used by peace and human-rights campaigners, which they are using to mobilise thousands of supporters throughout Europe.
The network, which is cheap to use and is accessed by 20,000 people world- wide, is also used to summon protesters to sites facing eviction and police raids.
But roadbuilding firms and Group 4, the security company guarding many road projects, have also accessed the network. Group 4 says it has subscribed to GreenNet, which allows it to read the campaigners' bulletins, for "environmental reasons".
"We are members of it and we use it as an information source. We are a company interested in environmental issues," said a spokesman.
Last month a raid on the British Roads Federation offices in south London, which was advertised on the GreenNet, was thwarted after the BRF learnt of the plans. Campaigners who arrived to protest found the police waiting for them. A BRF spokesman said: "They advertised the protest among themselves. It was on the Internet at least a week before. I was advised by four different people that it had been advertised on the Internet."
Worried that their mail is being tapped by "enemy" organisations, campaigners plan to set up private communications lines conferences.
They are also planning to send sensitive messages, such as those on last year's occupation of the House of Commons roof, in code.
Last week Road Alert!, a campaign group co-ordinating direct action, called on activists through the GreenNet to support campaigners against the M77. An urgent bulletin posted after midnight said: "!!!Alert!!! The campaign has been tipped off that the main camp at Pollok Free State will be evicted from TODAY - PLEASE GET UP THERE ASAP!"
An update minutes later said: "Red Alert - Backdoor information suggests that another major move is imminent . . . today. It is hoped that if this reaches anyone within travel distance they will come to the camp as quickly as possible."
Another message to activists urged them to prepare for "the next tree- top battle" near the M65 in Lancashire: "There are 17 tree houses across the valley, with walkways. A new squat has now been taken close to the valley. Please get up there and help out."
Campaigners from Chile, Sweden and New Zealand have joined New Age travellers at protest sites such as an ancient wood near Glasgow threatened by the M77. Last week, Allan Stewart, the former Scottish Office Minister, wrote to the Home Secretary to check on the immigration status of the anti-road protesters.
The GreenNet, a non-profit organisation based in London, is part of a world-wide computer network of 20,000 human-rights, environmental and peace campaigners.
It has been established for 10 years but growth in subscriptions have doubled in the past six months as more and more campaigners link up.
Tim Allman, spokesman for Road Alert!, said: "The GreenNet has certainly made us more efficient. We work in smallish groups. M11 will plan a campaign and we will co-ordinate support. We would let campaigners know if there's a clash between two important actions and would try and get the times right for protests."
The system has been used by members of the M11 campaign and animal-rights campaigners protesting over veal calves.
The Freedom Network, a UK-wide organisation of activists involved in protests against the Criminal Justice Act, used the network to co-ordinate direct actions - such as the sit-in in the garden of Michael Howard, the Home Secretary - until its computer was stolen last December.
Lawyers offering free legal advice to campaigners are also linked to the GreenNet. One of these is barrister Peter Gray who gives New Agers advice on how to deal with the police and court appearances.
He said: "The type of people who are against road building are the type who need legal advice. I've started doing a regular series of notes on common legal situations, such as how to act in court and on the powers of the police. I also answer specific queries from protesters who have got into trouble."
Other users of the GreenNet include War Resisters International, the Nicaragua Solidarity Campaign and the International Peace Bureau.Reuse content