Chambers' practice of awarding unfunded pupillages is contrary to the National Minimum Wage Act, says an opinion produced for the Bar Council.
In 1997-1998 nearly 200 pupillages out of a total of 700 were unfunded.
The opinion, produced by Jeremy McMullen QC, Jennifer Eady and Sarah Moor, advises the Bar Council that pupils aged 26 and over qualify for the national minimum wage.
"Barristers have lagged behind solicitors for many years when it comes to rights and conditions at work for trainees and others attached to chambers," says Gordon Nardell, a barrister at 6 Pump Court specialising in human rights and EU law, and who is involved in Bar education and training.
He believes that the applicability of the legislation to pupillage has a wide significance for the structure and attitudes of the Bar.
"The old fiction that these people have no rights because they are self-employed is just unsustainable at the end of the 20th century. It fails to recognise the reality of power relationships in a set of chambers. The modern Bar needs to extend a culture of rights into all aspects of the training and recruitment of junior members of the profession," he says.
"Those sets who have ignored Bar Council recommended practice on pupillage awards may well be up in arms, but I don't have much sympathy for them," remarks another barrister.
However, one senior clerk is dismissive of its application.
"I cast great doubt on whether it is appropriate to chambers," he says.
A Bar Council spokesman says: "We have a responsibility to inform our members of the implications of new legislation."
The Bar Council has also been advised that all first six and most second six pupil barristers are entitled to the protection of the Working Time Regulations 1998.