Barristers were warned by the Office of Fair Trading yesterday that their professional body faces tough penalties unless unnecessary restrictive practices are brought to an end.

John Vickers, director general of fair trading, said he was "ready to use" his powers to fine the Bar unless it improved public access to its members.

Mr Vickers said that although the Bar had made some progress in ending centuries-old restrictions on its profession there was a need for greater liberalisation.

In its report published yesterday the OFT rejected the Bar's argument that it was not in the public interest to allow barristers to conduct litigation – a job currently performed by solicitors.

The Bar has argued that this would end the differentiation between barristers and solicitors, and lead to a single fused legal profession.

But Mr Vickers said that the ban on barristers conducting litigation restricts the public's freedom of choice and leads to "inefficiencies".

"Where this is the case the OFT is ready to use its available powers to remove unnecessary restrictions that work against the interest of consumers," he warned in yesterday's progress report.

Mr Vickers also questioned the need to continue with the rank of Queen's Counsel (QC). He said that awarding senior barristers silk did not offer "value to consumers", and he said this was due in part to the perceived lack of transparency in the appointments system and the absence of any power to deprive poor-performing QCs of their title.

Mr Vickers acknowledged that the future of the QC system is a matter for the Lord Chancellor, Lord Irvine of Lairg, who will be consulting on the issue later this year.

But he remained concerned about other practices that could be shown to distort the legal market-place, such as the ban on barristers conducting litigation.

Under the Competition Act 1998 the OFT has the power to fine companies and professional bodies, such as the Bar Council and the Law Society.

In a preliminary report published last year, Mr Vickers recommended wholesale changes to the way barristers and solicitors conduct their businesses. Yesterday he said that more has been achieved in one year in terms of direct access to barristers than in the entire history of the profession's existence.

"We welcome the fact each of the professional bodies concerned has taken some positive action towards removing unjustified restrictions. And some restrictions have been justified. But there is important unfinished business."

This week the Bar announced its own consultation exercise to allow the public greater access to barristers.

One proposal included allowing barristers to offer their services directly to clients in police stations. Guy Mansfield QC, chairman of the Bar Council's legal services committee, said: "This may be the most controversial part of the consultation paper, and much depends on the views of criminal practitioners."