The Supreme Court dismissed a challenge to the Quality Assurance Scheme for Advocates (QASA).

Lords Reed and Toulson ruled that the controversial accreditation scheme was the “only way” to provide the desired level of protection to the public, and confirmed that it was lawful and proportionate.

Previously, the High Court and Court of Appeal had also rejected the attempt to overturn the Legal Service’s Board’s approval of the scheme granted in 2013.

The challenge to QASA, which was designed by the three main legal regulators – the Bar Standards Board, Solicitors’ Regulation Authority and CILEx Regulation – had been brought in the name of four criminal barristers.

Welcoming the judgment, Dr Vanessa Davies, BSB director general, said: “The objective of providing a high level of public protection through a precautionary scheme has long been the underlying principle behind QASA.

“Given the length of time that has passed since the scheme was approved by the LSB, we need to consider the scheme’s implementation and likely timescales involved.”

The Criminal Bar Association, which financially backed the challenge, said it was “deeply disappointed” by the ruling. It added: “The CBA remains of the view that the scheme is a bad one.”

Meanwhile the BSB has begun a consultation on reforming its disciplinary tribunal system.

Proposed changes include modernising terminology, reducing the role of the Inns of Court, extending the regulator’s ability to appeal the outcome of disciplinary tribunals and limiting the costs claimed by barristers who represent themselves.

The BSB is also seeking views on measures to mitigate the costs of the disciplinary system, replacing all five-person panels with three-person panels, and shifting the decision on the readmission of disbarred barristers from the Inns of Court to itself.