The Supreme Court has just issued its judgment in the case of Shergill v Khaira  UKSC 33 an appeal from the Court of Appeal decision Shergill v Khaira  EWCA Civ 983
The case involved a dispute between two groups of Sikhs and the trusteeship of two Gurdwaras (Sikh places of worship). Essentially the Trustees had been removed by Sant Baba Jeet Singh Ji Maharaj, who claimed to be "the Third Holy Saint" and successor to "the First Holy Saint", who was the founder of the Gurdwaras in the 1980s. The Claimants asserted that Sant Baba Jeet Singh Ji Maharaj was not in fact "the Third Holy Saint" and therefore was not entitled to remove them.
In the Court of Appeal it was held that the issues in the case would require the Court to adjudicate on matters of Religious Belief or Doctrine and as such were inherently "Non Justiciable"
The principle that issues of Religious Doctrine and Belief are non justiciable in the UK Courts is of long standing. In the House of Lords case of Free Church of Scotland v Overtoun  AC 515, at page 643, Lord Davey said
“My Lords, I disclaim altogether any right in this or any other civil court of this realm to discuss the truth or reasonableness of any of the doctrines of this or any other religious association”
4) This principle was restated with clarity in Blake v Associated Newspapers Ltd  EWHC 1960 (QB) where Mr Justice Gray said
.. It is well-established by such cases as General Assembly of Free Church of Scotland v. Lord Overtoun  AC 515; R. v. Archbishops of Canterbury and York ex parte Williamson (transcript from M Hill, Ecclesiastical Law, 2nd Ed, OUP, 2001 at 672-676) and Varsani v. Jesani  CH 219 that the court will not venture into doctrinal disputes or differences.
And also by the House of Lords in Secretary of State for Education and Employment ex parte Williamson  UKHL 15 where Lord Walker said
 . For the Court to adjudicate on the seriousness, cogency and coherence of theological beliefs is (as Richards J put it in R (Amicus) v Secretary of State for Trade & Industry  IRLR 430, 436-7, para 36) to take the Court beyond its legitimate role.
In HH Sant Baba Jeet Singh Ji Maharaj v Eastern Media Group & Anor  EWHC 1294 (QB), and Shergill v Purewal & Anor  EWHC 3610 (QB), Mr. Justice Eady and Sir Charles Gray respectively stayed Libel proceedings on the grounds that they would inevitably involve the Court adjudicating on issues of Sikh doctrine and belief and as such were non justiciable issues
The rationale and justification for this principle of Non Justiciability in matters of religious dispute was set out by Lord Justice Mummery in his judgment in Shergill v Khaira  EWCA Civ 983
 , non-justiciability is a salutary principle of judicial self-restraint. It ensures that judges do not overreach themselves and that they abstain from deciding questions that are neither appropriate for, nor capable of decision by, judicial method. Judges are not capable of understanding and deciding everything and it is not their function to do so. Judges are not omniscient. The courts they sit in are courts of law. There are matters on which a court is not competent to speak with authority, because of the limitations inherent in the nature of the judicial process, and therefore should not speak. That is so where the questions are not matters of law at all, such as subjective inward matters incapable of proof by direct evidence or by inference”.
Faced with this century of consistent legal authority one might have expected the Supreme Court to have agreed with Mummery however the Supreme Court made a rather subtle distinction of its own which may or may not erode the concept of Non Justiciability in future cases
 where a claimant asks the court to enforce private rights and obligations which depend on religious issues, the judge may have to determine such religious issues as are capable of objective ascertainment. The court addresses questions of religious belief and practice where its jurisdiction is invoked either to enforce the contractual rights of members of a community against other members or its governing body or to ensure that property held on trust is used for the purposes of the trust
 The law treats unincorporated religious communities as voluntary associations. It views the constitution of a voluntary religious association as a civil contract as it does the contract of association of a secular body: the contract by which members agree to be bound on joining an association sets out the rights and duties of both the members and its governing organs. The courts will not adjudicate on the decisions of an association’s governing bodies unless there is a question of infringement of a civil right or interest. An obvious example of such a civil interest is the loss of a remunerated office. But disputes about doctrine or liturgy are non-justiciable if they do not as a consequence engage civil rights or interests or reviewable questions of public law
In this case the SC held the issues essentially involved the interpretation of a Trust rather than any asjudcation on the correctness or otherwise of religious doctrines. In para 53 the Court returned to the founding authority on Non Justiciability Free Church of Scotland v Overtoun  AC 515 and said
as Lord Davey said in Free Church of Scotland v Overtoun (at pp 644-645) the civil courts do not have the right "to discuss the truth or reasonableness of any of the doctrines of [a] religious association". He stated
"The more humble, but not useless, function of the civil Court is to determine whether the trusts imposed upon property by the founders of the trust are being duly observed."
The fact that the Supreme Court still clearly considers Overtoun to be good law will probably prevent this new decision opening up Court to arguments about religious doctrine but the decision has pushed the door of Non Justiciabilty open by a crack and time will tell whether that crack will be pushed open further in the future