Law: Corridors of power lead to the lobby: Barbara Lantin meets Richard Thomas, who has become the first director of public policy at Clifford Chance

In Washington, they talk of the revolving door through which lawyers and others pass as they move from government to private sector and back again. The British equivalent may be more of a Berlin Wall, but it is traversable - as Richard Thomas has proved.

Two years ago, he was coming to the end of a six-year stint as Sir Gordon Borrie's deputy in the consumer affairs division at the Office of Fair Trading. Today he sits on the other side of the wall as the first director of public policy at Clifford Chance - one of the country's very few lawyer lobbyists.

'I was coming to the end of my time at the OFT and wondering where my future lay,' he says. 'It occurred to me that I could combine my background as a lawyer with my knowledge of Westminster, Whitehall and the European institutions. In Washington, lawyers are heavily involved in this sort of activity but in London it is virtually unheard of.'

Before Mr Thomas could approach the top London firms, Clifford Chance approached him. They had been considering setting up a public policy department for some time and were trying to identify the person to head it. The match was made.

For Richard Thomas, the job is just another 'first': in the first batch of lawyers to be employed full-time by a citizens' advice bureau; first legal officer at the National Consumer Council; and the first non-civil servant to be director of consumer affairs at the OFT.

The surprise is therefore not that Mr Thomas is in this plum job, but that the job exists at all. Why did Clifford Chance feel the need to go down this particular avenue? 'Market research suggests that a lot of Clifford Chance's clients - particularly the international clients - want their lawyers to be involved this area.

'Also, law firms in general - and this firm in particular - are pushing out the boundaries of legal practice. There are no hard and fast rules about what lawyers do and don't do any more. This firm has a high reputation and so people see us as their business advisers in the broadest possible sense. I think it's part of a return to the 19th-century idea of the solicitor as a man of affairs rather than a technician.'

The work splits into three interconnected parts - anticipation, analysis and advocacy. The first involves monitoring developments in legislation here and abroad that might affect business clients. The department produces a weekly diary for internal circulation, highlighting areas of likely interest and papers on major pieces of legislation. The morning after the Queen's Speech a 20-page guide lands on clients' desks. Accountants have been doing this kind of thing for years with the Budget, but it is new ground for solicitors.

Having identified the main areas of client interest, the public policy group advises on how best to deal with imminent legislation. 'Our aim is help the client clarify his objectives, and achieve these through reasoning and persuasion,' Mr Thomas says.

'The really important thing is to get involved at an early stage. In one case I dealt with soon after I came here, the client had realised that some regulations were in prospect which presented quite a problem for the company. They had not been drafted at that stage and we were able to devise an approach which enabled the Government to achieve its objectives in a way which was more acceptable to our clients.'

After 15 years spent close to the corridors of power, Mr Thomas is well placed to influence the lawmakers. He cut his lobbying teeth on the Supply of Goods and Services Act, a private member's bill which he steered through Parliament while at the National Consumer Council. Other successes followed, but he insists that being an effective lobbyist depends more on what you know than whom.

'People think that lobbying is about having a drink with the minister,' he says. 'Much more important is an insight into the Whitehall and Brussels structures, procedures and culture.

'Not many people outside the system know the pecking order, or the level at which decisions are taken. I am not saying the civil service is more important than Westmister, but you ignore the administration at your peril.'

But why should anybody choose to go to a lawyer for this service, rather than to a specialist lobbying firm? 'Some issues obviously have a high legal content and it makes sense to combine a full understanding of the legal situation with skills in handling the political dimension,' Mr Thomas says.

'Also, there's an underlying concern that some kinds of lobbying don't enjoy a high reputation and that the professional standing and skills that lawyers can bring to this activity can avoid these problems. That is why we tend to go for a low- profile approach. We don't go in with all guns blazing or crow about our successes - and not just because of client confidentiality.'

In the past two years, Mr Thomas has been involved in some 400 cases covering everything from private finance initiatives in the public sector to product safety, from transport to trademarks. He sees himself not as a self-contained unit but as a resource to be used by the specialist lawyers when appropriate.

'I have had to become familiar with a wide range of subjects at a superficial level and at the same time to familiarise others in the firm with the techniques of public-sector processes. Part of my strategy is to increase the awareness of public policy matters across the firm.

'The aim is to give lawyers in other departments and in our other offices across Europe the confidence to handle these issues, so that they can see the broader picture when dealing with clients and influence policy when necessary. That is why no consideration was ever given to setting up the public policy group as a separate lobbying organisation. It is integral to the firm.'

Public policy without a legal element is not likely to be a client- puller in its own right, but Mr Thomas now features in beauty parades for new business and feels that his work offers added value for existing and potential clients.

'Clients appreciate that there could be a political dimension to their cases even when it is not obvious,' he says. 'The signals I am getting both inside and outside are that this is a logical and sensible activity for a law firm to be engaged in, and that it is likely others will want to do more.'