50 Shades of Obiter

Amy Woolfson gets her Latin on to explain the concept of obiter…

What’s authoritative?

The English legal system is founded on the doctrine of stare decisis, often translated as ‘let what has been decided stand’. Put simply, a court will follow the decisions of those courts which it is bound by, where the material facts of the case under consideration are the same as a previously decided case.

New law students soon learn that judgments contain two types of reasoning. There is the ratio decidendi, usually shortened to ratio, which roughly translates as ‘the reason for the decision’. This is the core of a decision, where the judge states what the law is, as it specifically applies to the facts of the case. All cases have a ratio, and where the court deciding the case is sufficiently senior (i.e. the High Court or above), that ratio will be capable of binding lower courts. 

What’s obiter?

Any judicial reasoning that is not core to a decision is classed as obiter dicta, or just obiter, which can be translated as ‘things said by the way’. This is not capable of binding a lower court but it can be persuasive. One example of this is dissenting judgments, where a judge may disagree with his or her colleagues as to what the outcome of a case should be, or agree as to what the outcome of the case should be but give different reasons for doing so. Other sources can be persuasive too, including overseas judgments, Hansard (the official report of what is said in Parliament) and Law Commission reports. 

What’s the point of obiter?

Well, despite hundreds of years of reported English cases, novel situations still pop up. Often, there will be no clear authority that applies to the facts. Or perhaps the ratio of the leading case, when applied to the facts of your case, does not produce the result that justice (or your client) demands. This is when persuasive sources become invaluable to making a legal argument. The task of the lawyer or the law student is often to explain why one persuasive argument should be considered more persuasive than another.

Is all obiter the same?

Well no: hopefully by now you are realising that there are in fact, many shades of obiter. When using an obiter source, it is vital to recognise how persuasive it is and treat it accordingly. Here are a few ideas to help with this:

  • Who said it, and where?

In case law, the more senior the judge, the more persuasive the obiter is likely to be. So a statement that forms part of a dissenting judgment in the Supreme Court is likely to be more persuasive than the same statement made in a dissenting judgment in the Court of Appeal.

When considering overseas judgments, jurisdictions which were founded in the English common law can be a useful source of obiter. But be aware that over time, the country’s legal system may have diverged significantly from ours. For example, both Australia’s and New Zealand’s legal systems have their foundation in the English common law. But while Australian authorities on tort can be useful, legislative developments in New Zealand since the 1970s have made the Kiwi authorities less helpful. 

The Judicial Committee of the Privy Council can be viewed as a hybrid between a domestic and an overseas court. It is the highest court of appeal for a number of current and former Commonwealth countries (such as Jamaica and Mauritius), crown dependencies like Jersey and Guernsey, overseas territories and military sovereign bases. The Judicial Committee of the Privy Council does not form part of the hierarchy of courts in England and Wales and so its judgments are not binding here. But some of the judges from the Supreme Court also sit on the Privy Council, meaning that their judgments can be highly persuasive. See R v Mohammed [2005] EWCA Crim 1880, where the Court of Appeal chose to apply a Privy Council judgment over a House of Lords judgment that was widely considered defective.

  • What happened next?

Obiter does not stand still. It can become more or less persuasive over time. So it is vital to check what has happened since the statement you are seeking to rely on was made. 

For example, if the Law Commission (the independent body tasked to review and recommends reforms of English and Welsh law on behalf of Parliament) has proposed a change in the law, this can be persuasive. But if the proposal has been roundly condemned, or just plain ignored by the politicians then it will become less persuasive or not persuasive at all.

On the other hand, obiter comments sometimes become elevated beyond their original status. A classic example of this is Lord Denning’s comments in Central London Property Trust v High Trees House [1947] K.B. 130. In it, Denning stated that an action to recover full rent where the landlord had agreed to a reduction for the duration of World War II would have failed. As the landlord was only seeking to recover rent from after the war had ended, these comments could only be obiter but nonetheless the comments have been followed in subsequent cases and High Trees is often described as the foundation of the law on promissory estoppel.


The doctrine of stare decisis might at first suggest that the authoritative argument will always win. But as stated above, there will not always be an authoritative argument that fits squarely with the facts of your case. Knowing how to evaluate and deploy persuasive authorities with confidence will help you to win arguments that are on the margins. And that’s where a lot of the interesting stuff happens in law.

Amy Woolfson recently graduated from the Open University. Read all her blogs for Lawyer 2B.