In Hedley Byrne & Co Ltd v Heller & Partners Ltd the rule was established that irrespective of contract, if someone who possesses a special skill undertakes to apply that skill for the assistance of another person who relies upon that skill, a duty of care will arise. The fact that the barrister did not enter into a contract with his solicitor or client ceased to be a ground of justification for the immunity.
Nevertheless, in a unanimous decision, Lord Reid said in Rondel v Worsley (1969) 1 AC 191 at 227 that the ancient immunity should be continued on considerations of "public policy [which are] not immutable." (see Roxburgh: 1968). In Saif Ali v Sydney Smith Mitchell & Co. (1980) AC 198 the scope of the immunity was considered. Lord Wilberforce said at 213 that "...barristers . . . have a special status, just as a trial has a special character: some immunity is necessary in the public interest, even if, in some rare cases, an individual may suffer loss." (see Hill: 1986) When s51 Supreme Court Act 1981 (substituted by s4 Courts and Legal Services Act 1990) introduced the power to make wasted costs orders against legal practitioners, Ridehalgh v Horsefield (1994) Ch 205 ruled that orders could be made against barristers personally.
As to criminal trials, prosecuting counsel owes no duty of care to a defendant: Elguzouli-Daf v Commissioner of Police of the Metropolis (1995) QB 335. If a defendant is convicted after a full and fair trial, the remedy is to appeal. An attempt to challenge the convictions by suing the defence advocate would be an abuse of process: Hunter v Chief Constable of the West Midlands Police (1982) AC 529. If any challenge is to be made following an unsuccessful appeal, the only legitimate avenue would be the Criminal Cases Review Commission even though the body is under-resourced. But the question remained as to whether a civil action might be maintained if the appeal was successful (see Cane: 1996).
In Arthur J.S Hall and Co. v Simons (2000) 3 AER 673, the Lords re-evaluated the public policy issues. The critical factor was the duty of a barrister to the court under ss27(2A) and 28(2A) Courts and Legal Services Act 1990 (inserted by s42 Access to Justice Act 1999). The question was whether the immunity is needed to ensure that barristers will respect their duty to the court.
In 1967, the answer was that assertions of negligence would tend to erode this duty and accorded a special status to barristers. Nowadays a comparison with other professionals demonstrated that barristers' immunity against being sued in negligence was anomalous. Allowing civil action was unlikely to produce a flood of claims and, even if some claims did emerge, a claimant alleging that poor advocacy resulted in an unfavourable outcome would face the very great difficulty of showing that a better standard of advocacy would have resulted in a more favourable outcome.
Unmeritorious and vexatious claims against barristers are simply struck out. Thus, it was no longer in the public interest that the immunity in favour of barristers should remain in either civil or criminal cases. This did not imply that Rondel v Worsley was wrongly decided. But in today's world, that decision no longer correctly reflected public policy. The basis of the immunity of barristers has gone. And exactly the same reasoning is applied to solicitor advocates.