The High Court has found that the Personal Injuries Assessment Board's policy of dealing directly with clients, rather than through their solicitors, is outside the powers conferred on it by legislation.
The Chairperson of the PIAB, Dorothea Dowling, said the board was 'astonished' by the judgement.
The challenge to the policy was taken by a Co Offaly meatboner. The Law Society was also a party to the proceedings.
Mr Justice McMenamin found that the relevant section of the legislation establishing the PIAB did not contain a specific power enabling it to adopt this procedure.
He said the right to legal representation and the lawyer/client relationship existed in the common good and helped to guarantee equality in litigation and the maintenance of fairness between the strong and the weak.
The Law Society had argued that the issue of the PIAB's entitlement to disregard written authorisation of an applicant to communicate solely with his or her solicitor went to the heart of the solicitor/client relationship and the ability of a solicitor to represent a client.
The Minister for Enterprise, Trade and Employment, Micheal Martin, said that he would examine the judgment in detail, but said that he remained committed to the PIAB objectives of reducing the cost of providing compensation and the amount of time it took to process claims.
But Brendan Howlin, Labour's spokesperson on enterprise, trade and employment said that today's High Court judgment was both welcome and inevitable, saying the people who wished to engage and speak through a solicitor should be allowed to do so.