The Bar Council is reviewing its official backing of BDO Stoy Hayward's annual Bar survey after the accountancy firm accidentally leaked confidential information about chambers to rival sets.

Sources at the Bar Council have confirmed that the relationship it forged with the firm back in 1999 in order to give its annual survey quasi-official status may now come to an end.

The move follows a computer error at BDO Stoy Hayward in June this year that saw a number of sets receiving other chambers' previous submissions.

As well as angering those chambers caught up in the blunder, the affair has shaken the Bar Council's confidence in the survey, which had come to be regarded as the benchmark for the Bar.

The mix-up is also likely to be a key factor behind a significant drop in the proportion of chambers responding to the survey – from a record high of 46% last year to 31% for the 2002 survey, which was unveiled last month.

One senior clerk at a leading commercial set that was caught up in the mistake said the error had persuaded him not to complete this year's questionnaire.

A Bar Council source said: "It is no secret that we were disappointed about the leak – but there is also a feeling that we may need to approach the survey in a different way, or that it might even be time to give it a rest."

One factor behind the review is the Bar Council's desire to gain more statistical information about policy issues such as direct access and student funding – as opposed to economic information about the performance of chambers.

Peter Bennett, chief executive of leading Chancery commercial set Maitland Chambers, maintained reservations. He said: "We recognise that it provides valuable information, but we would need to be totally convinced that confidentiality would be maintained before participating next year."

A BDO Stoy Hayward spokeswoman said it was reviewing the survey in conjunction with the
Bar Council. She added the firm was waiting to meet incoming Bar Council chairman Matt Kelly QC before determining the report's future.