Judicial salaries are decided following the recommendation of the Senior Salaries Review Body (SSRB), and are a matter of public record.
The SSRB provides independent advice to the Prime Minister, the Lord Chancellor and the Secretary of State for Defence on the remuneration of the judiciary, senior civil servants, senior officers of the armed forces, Members of the House of Commons, Members of the House of Lords and other groups that are referred to it from time to time. Appointments are made by the Prime Minister.
Although judicial salaries are certainly higher than the average wage for England and Wales, it is worth noting that a successful solicitor or barrister from a top firm or Chambers can earn many times more than even a senior judge.
Research carried out in 2008 by Professor Hazel Genn showed that many highly qualified lawyers were put off applying to join the High Court because they could earn up to 3 times more in their current post than they could as a judge!
More information – including the exact salaries paid to each type of judge – is available on the on gov.uk (external link).