20th century reforms
Although until the outbreak of the Second World War appeals continued to be heard only by qualified professional judges, convention dictated that these were heard in the Chamber of the House of Lords.
In 1948, however, noise caused by workmen repairing bomb damage to the Palace of Westminster forced the Law Lords to move to a committee room and form themselves into an Appellate Committee in order to hear appeals.
Judgments were still given in the Lords Chamber, although they ceased being read out in full in 1963. With appeals being heard away from the Chamber, it also proved more difficult for Lord Chancellors to participate in the judicial work of the House, although they continued to do so on occasion until 2001.
Europe and devolution
The status of the House of Lords as the UK's highest court of appeal was altered when the UK became a member of the European Community (EC, later the European Union) in 1973. This introduced a further appeal from the Lords to the European Court of Justice, although only on matters concerning EC law. Since the passage of the Human Rights Act in 1998, the Lords also acquired the power to declare a law incompatible with the European Convention on Human Rights.
Meanwhile the Judicial Committee of the Privy Council heard a decreasing number of appeals from courts in independent Commonwealth nations (those from New Zealand, for example, ceased in 2003).
However it acquired a new role following the devolution of certain legislative powers to the Scottish Parliament and National Assembly for Wales in 1999, and the Northern Ireland Assembly in 2000. It began to hear cases on the competency of the devolved bodies and precedents set by its judgments on "devolution issues" became binding on all other courts, including the House of Lords.