linguistic:paraphrasing, information:highlighting
The Supreme Court's ability to override its own precedent

The British House of Lords, as the court of last appeal outside Scotland before it was replaced by the UK Supreme Court, was not strictly bound to always follow its own decisions until the case London Street Tramways v London County Council AC 375. After this case, once the Lords had given a ruling on a point of law, the matter was closed unless and until Parliament made a change by statute. This is the most strict form of the doctrine of stare decisis (one not applied, previously, in common law jurisdictions, where there was somewhat greater flexibility for a court of last resort to review its own precedent).

This situation changed, however, after the House of Lords issued the Practice Statement of 1966. The House of Lords decided to allow itself to adapt English law to meet changing social conditions. In R v G UKHL 50, the House of Lords overruled its 1981 decision in R v Caldwell, which had allowed the Lords to establish mens rea ("guilty mind") by measuring a defendant's conduct against that of a "reasonable person", regardless of the defendant's actual state of mind.

However, the Practice Statement was seldom applied by the House of Lords, usually only as a last resort. Up to 2005, the House of Lords rejected its past decisions no more than 20 times. They were reluctant to use it because they feared to introduce uncertainty into the law. In particular, the Practice Statement stated that the Lords would be especially reluctant to overrule themselves in criminal cases because of the importance of certainty of that law. The first case involving criminal law to be overruled with the Practice Statement was Anderton v Ryan (1985), which was overruled by R v Shivpuri (1986), two decades after the Practice Statement. Remarkably, the precedent overruled had been made only a year before, but it had been criticised by several academic lawyers. As a result, Lord Bridge stated he was "undeterred by the consideration that the decision in Anderton v Ryan was so recent. The Practice Statement is an effective abandonment of our pretension to infallibility. If a serious error embodied in a decision of this House has distorted the law, the sooner it is corrected the better." Still, the House of Lords has remained reluctant to overrule itself in some cases; in R v Kansal (2002), the majority of House members adopted the opinion that R v Lambert had been wrongly decided and agreed to depart from their earlier decision.