Karel Vinck, a veteran Belgian businessman who advises the European Commission on railway policy, has a simple answer to why road and air travel are cheaper than high-speed rail in Eur-ope. "They have better lobbyists," he quips.

He also says the usually state-owned railways have lacked vision and a united message to put across. But his comments reflect the power of lobbyists in the European Union.

The Commission may police a single market of 490m people but its small bureaucracy relies on contributions from interested parties to inform its decisionmaking. Members of the European parliament have few expert staff and it is not unheard of for them to adopt wholesale amendments to legislation drafted by lobbyists or non-governmental organisations.

"We are the oil that greases the wheels of the machine," says Tony Long, who runs the Brussels office of WWF, the conservation agency.

About 80 per cent of legislation applicable in the 27 member states emanates from Brussels, initiated by the Commission and implemented by the parliament and the Council of the EU. The Commission also governs the single market, competition and trade policy. So it is no surprise that lobbyists are flocking to Brussels.

The plastics industry has become the first to disband its national advocacy groups in favour of an EU-wide one. Wilfried Haensel, ex-ec-utive director of Plastics Eur-ope, representing polymer producers, says: "Our companies are global. There is no national interest."

Key to a lobbyist's success in shaping policy, says Thomas Tindemans, a consultant at law firm White & Case, is having a vision and answers to problems: "You need to come up with a solution for the problem of the decision-maker, not just a solution for you. 'No' is not an amendment."

Local knowledge helps. "You have to know the process. If it is legislation you can go to the Commission, parliament and Council. If it is the implementation, you go to national governments. The skill of lobbying is to focus on the people who have the decision--making power," he says.

Increasingly that is European MPs. After the Treaty of Lisbon reforms the bloc, the parliament will gain power over almost all policies. Alex Stubb, a centre-right Finnish MEP, says the numbers of lobbyists pitching up at his office are growing regularly. He is pushing through legislation that would increase registration re-quire-ments but he tries to listen to as many as possible. "All lobbyists are created equal," he says.

Daniel Gueguen, a veteran French lobbyist who came to Brussels in the 1970s and runs Clan Public Affairs, says building coalitions is vital. NGOs have been better at that than business.

While using Brussels-based lobbyists can save time in reaching key people, they are also useful for their knowledge of the policy process. "If you have a good case to make, you can pick up the phone and get a hearing," one consultant says. It also helps to have the unions on side.

Brussels has adopted the Continental-style "social partnership" between bosses and labour. The European Trade Union Confederation is consulted on policy and its leader has regular meetings with the Commission president. Unions protesting about job losses hold considerable sway with MEPs. Dock workers who rallied outside the parliament in Strasbourg in January 2006 succeeded in having a plan to open ports to more competition thrown out.

Such direct action may not be open to companies but energyintensive industries such as steel did fight a successful campaign over plans to force them to pay for permits to emit carbon dioxide. They claimed it would force them out of Europe to countries with no scheme to combat global warming.

It cannot have been unhelpful that workers at an Arcelor-Mittal plant in Liège held the first "carbon strike" days before the Commission published its plans. They were demanding Belgium be granted more free emissions permits. Without them, the plant would shut, management said.

Officially, the ways of Brussels are secretive. Except for the parliament, most discussions are private and minutes of meetings can be hard to come by. However, so many parties with different interests are involved - from rival Commission directorates to national representations - that it is not difficult to find out what is going on.

"It's not hard to get hold of documents. They get leaked to test the reaction to them," says one industry representative.

In the more legalistic world of competition policy, however, things are slightly different. Here, the Commission has formidable reg-ulatory powers - to vet company mergers, for example, or deem certain business practices illegal and impose hefty fines. Yet most lawyers advising companies in this area caution that lobbying has, at most, a limited role, and that cases are predominantly decided on their merits. One formidable reason for this is that decisions by the Commission are subject to judicial scrutiny - and the courts have been increasingly willing to make embarrassingly public reversals for the Commission when procedures have gone awry .

No one pretends lobbying does not go on - nor that companies, quite justifiably, may seek to have their views heard across the wide spectrum of Brussels forums. Such activity, lawyers tend to agree, is most successful when undertaken discreetly and early in the process.

One particularly tempting route may be to make the case to other departments within the Commission, especially if there are associated issues that fall within their remit. After all, the more difficult competition-related decisions usually require the approval of the whole college.

But even here, the competition officials guard their mandate carefully. Take the recent GoogleDouble-Click merger. This raised privacy and data protection issues which critics of the deal emphasised, and some other commissioners looked on closely. But from the outset, Neelie Kroes, the EU competition commissioner, was clear that it would be decided on comp-etition grounds alone. When the green light was finally given, the Commission statement carried only a brief rider about privacy obligations under EU law.

All that said, lobbyists point out that their role is not confined simply to securing a successful outcome in front of the Commission. It can also involve handling the reputational fallout from those proceedings - at its simplest, share price movements, say, or the impact on longer-term corporate strategies.

"One can help to ensure that the process works and one can also help with the impact of that process," says Mathew Heim, a competition specialist and consultant at The Centre in Brussels.

Calls for US-style controls in Europe's corridors of power

Love them or loathe them, an estimated 15,000 lobbyists are in Brussels. No one knows the real number because it is not mandatory to register and it depends which bodies you count.

Individual companies have offices and also use industry federations, such as Eurofer, which represents the steel industry. They and foreign governments also turn to public affairs consultancies and, increasingly, law firms. Then there are non-governmental organisations such as Greenpeace, the environmental group, or Beuc, which represents Europe's consumer groups.

Some also count the embassies of member states and self-governing regions, where staff track and try to shape policy.

As Brussels grows more powerful, transparency campaigners have begun to call for US-style controls on lobbyists. Siim Kallas, the administration commissioner, this year launches a voluntary code requiring signatories to say who their clients are and round figures of what they spend. Anyone could consult the register online and officials could be reluctant to meet those who refuse to join it, he says.

The European parliament, which gives access passes only to those who sign a code of conduct, is also tightening its procedures amid public concern and could adopt the same register as the Commission.