The introduction of mandatory minimum incomes for pupils next year will lead to a 23% slump in the number of pupillages being offered by chambers, this year's BDO Stoy Hayward barristers' survey has predicted.

The finding highlights the financial pressures faced by key sectors of the Bar – although commercial and Chancery arms continue to expand.

Twenty-four per cent of the chambers that responded to the survey said the new minimum pupillage award of £10,000, to be introduced in January 2003, would force them to reduce the number of pupillages they offer.

BDO Stoy Hayward estimates this will reduce the number of pupillages being awarded by 139, from the current figure of around 600.

However, Bar Council chairman David Bean QC pointed out that the number of law firm traineeships had dipped, and then bounced back, after the Law Society introduced minimum trainee salaries more than a decade ago.

"It may be that chambers are taking a conservative view of their ability to meet the compulsory pupillage funding requirements," he said.

"A potential dip was always foreseen by us and we expect the availability of pupillages to follow a similar pattern to that which occurred when the Law Society introduced minimum trainee wages in the late 1980s and early 1990s."

Other key findings in the report were that 94% of the 370 junior barristers who responded still owed money, with 41% reporting that they had not even started to pay off their debts.

However, the survey revealed that the Bar's overall income was still rising – to an estimated figure of between £1.4bn and £1.6bn this year, from a range of £1.3bn to £1.5bn in 2001.

And while income within criminal and family sets remained broadly static, the report said receipts at Chancery and commercial sets had shot up by 33%.

However, the rise is partly explained by the fact that chambers have continued to get larger – with 42% of the chambers that responded to the survey increasing their tenant count by more than 10%.

The annual survey, which has become a benchmark for the Bar, ran into trouble in June this year, when a computer error resulted in a number of sets receiving other chambers' previous submissions.

Thirty-one per cent of the chambers in England and Wales took part, down from a record high 46% last year.