They charge clients pounds 2,500 to pounds 5,000 a month for attempting to influence ministers and MPs on policy. For that, lobbyists will arrange meetings with MPs, get parliamentary questions put down, host lunches, teas or dinners with key policy makers and take members to the races, rugby matches at Twickenham or lavish parties.
Lobby companies are in touch with crucial groups such as the No 10 policy unit and senior civil servants.
Ian Greer - perhaps the most prominent lobbyist - prides himself on being personally acquainted with John Major and almost every member of the Cabinet.
It is such contacts that draw clients, who believe they lack the knowledge to negotiate the intricacies of parliamentary procedure, and the muscle to arrange such meetings on their own.
With more than 30 lobby companies now existing in Britain, many fear the rapid expansion of the industry in the last decade has given it disproportionate power.
Ian Greer Associates - at the centre of the present allegations and the first to launch in 1970 - is one of the best-known, along with Westminster Strategy, Westminster Communications, and GJW Government Relations.
Clients have ranged from the Police Federation - which hired lobby representation after the Sheehy report recommended changes to the way police operated - to Central and Lothian regional councils, which wanted representation for the local government Bill, British Airways, Coca-Cola, and Cadbury-Schweppes.
Issues that have been handled by lobbyists include the Channel tunnel rail link, moving the time of ITN's News at Ten, Sunday shopping and a fifth terminal at Heathrow.
Prominent MPs - classic examples are those who chair the influential Tory backbench committees on trade and industry and finance - will receive several letters a day from lobby companies hoping to set up meetings.
In return for their services, members can enjoy a succession of expensive meals and free trips. They may be offered lucrative consultancy fees, and if they agree to attend functions hosted by lobby companies for their clients, they also have the chance to make industry contacts that could lead to well-paid directorships.
Big companies will exploit all their assets in the quest to cultivate MPs.
One is well-known at Westminster for employing 'pretty young men' to build up relationships with the movers and shakers at Westminster. Others are said to ensure they employ unattractive or frumpy women who will not intimidate the fragile male egos at the House.
In the wake of concern about the spreading tentacles of their power, a select committee on members' interests recommended in July 1991 that the Commons establish a register in which professional lobbyists would have to reveal details of their business and list clients.
A second report, published the following March, urged that MPs state the kind of lobbying they were undertaking for them.
But others object to such strategies, notably the lobbyists themselves who maintain that criticism of their business is unfounded and that suggestions of sleaze are unjustified.
Andrew Gifford, chairman of the Association of Professional Political Consultants and chief executive of GJW Government Relations, said: 'I've been a lobbyist for almost 15 years and I've never thought of paying an MP for tabling a question.
'Most of our work is pretty dreary - monitoring, researching what's happening in Parliament, forthcoming legislation and that kind of thing.'Reuse content