Ms Faber, a partner in the London firm Richards Butler since 1988, specialising in commercial work, is to take up her five-year appointment at the Law Commission at the end of January.
The Commission consists of a chairman, normally a seconded High Court judge - at present Mr Justice Brooke - and four other commissioners who are required to be judges, solicitors, barristers or teachers of law in universities. Diana Faber will replace Trevor Aldridge, a former practising solicitor and a land law specialist.
'My appointment is something of an innovation,' she says. 'The Commission has never before had a member with particular responsibility for commercial and corporate law, but it was looking for someone with that experience.'
Her experience is, in fact, wide and varied. Ms Faber, who is aged 38 - the youngest commissioner ever appointed - practised as a barrister for four years before being admitted as a solicitor 10 years ago. She is a frequent speaker at public conferences both here and overseas and has published extensively on a number of areas of commercial law.
The Commission, which was set up in 1965, works according to Civil Service rules and its programmes are approved by the Lord Chancellor. It has autonomy, however, as to the policy it adopts on law reform.
But if its draft statutes are to become law, it has to find backing to take them through Parliament. So, if the commission produces something very different from government policy, explains Ms Faber, there is little chance of it becoming law. In general, therefore, its proposals are politically non-controversial. However, she says, its measures fail to get through more often because of lack of parliamentary time than their controversial nature.
Ms Faber's plan to counter this sort of problem is to lobby MPs and peers at an early stage in the proceedings. 'If you involve people right from the beginning, you are much more likely to have support at the end of the day when you want them to do something - that is, get our work through parliament,' she says.
'Bringing in the legislature at an early stage is an innovation. I hope I won't be disappointed in their response. I do not want to sit there for five years and have reports moulder on a shelf.'
The Commission's work is confidential only at the final report stage, when it becomes subject to parliamentary privilege. Up until that point, its wide consultative powers mean that all interested parties and the public at large may have access to its deliberations.
The tradition of the Commission is to get things absolutely right, Ms Faber says, which is why its papers are noted for being excellent expositions of the law. This means that the job of a commissioner entails a great deal of academic research. It also involves talking to everyone and anyone: chairmen of large public companies, their accountants and legal advisers, small businessmen, government departments and trade associations.
'I intend to talk to them face to face and find out what their problems are,' says Ms Faber. 'The Law Commission has always believed in consulting face to face, but I am not sure how much it has done along the lines I propose.'
Rather than sending prospective interviewees a vast and time-consuming questionnaire, she intends to provide one sheet containing single-point headings to be discussed at a succint - say 45 minutes - meeting. 'I suspect that will be a departure from normal civil service practice,' she says.
Her first task, referred to the Commission by the Department of Trade and Industry, will be to look at reform of certain areas of corporate law, one area being private companies. 'It is interesting that there is no definition of a private company in the legislation,' she points out.
'The man in the street tends to think of a private company perhaps as a sole trader, but in reality it could be a huge business. It's a major issue - whether all the complicated provisions of the legislation that apply to public companies should also apply to private companies.'
Ms Faber expects to receive a lot of feedback from small traders, because the legislation as currently framed makes it harder to do business. She is a passionate believer in commercial and corporate law that makes it easier to do business, while at the same time protecting the interests of the creditors and shareholders.
Another area of study will be financial assistance for the purchase of a company's own shares. 'This may arise when a company is restructuring to make it more efficient, or in a takeover,' Ms Faber explains.
'It may have a positive purpose, but it is necessary to have a balance of interest between the creditor and the shareholder, because the company's assets are depleted. It's seen to be a problem regularly in smaller transactions, as well as in one or two notable major cases, and often comes before the courts.'
Other areas in which Ms Faber hopes to become involved at the Law Commission include EDI - electronic data interchange - marine insurance, banking and multi- modal transport.
Law commissioners are appointed initially for up to five years; their contracts may be renewed for a further three. At a personal level, becoming a law commissioner could scarcely be bettered as a career move.
'It opens up the world,' Ms Faber says. 'In five, or maybe eight years' time I will still have a lot of working life left. I'm one of these people who never want to retire anyway. I could go back to private practice, or into academic life. I would also like to try sitting in a judicial position part-time - a move which is permitted to law commissioners - to see if I am suited to that sort of career.'