Judicial pension reforms could detonate a retention 'time bomb', the lord chief justice has warned in a report exposing the full extent of the judiciary's recruitment crisis.

In supplementary evidence to the Review Body on Senior Salaries, which advises the government, Lord Thomas of Cwmgiedd says several members of the higher judiciary have publicly stated they will refuse to join the 2015 Judicial Pension Scheme and leave the judiciary once their transitional protection ends.

The report suggests the government is still planning to appeal the employment tribunal's January decision that the transitional pension arrangements for 210 judges amount to unlawful age discrimination.

The lord chief confirmed that, from around 150 senior judges, 34 are retiring in 2016-17, more than double the norm in previous years. More than 100 new High Court judges could be needed in the next five years. Despite trying to recruit 25 High Court judges in January 2017, by October the 108-strong High Court cohort will be down 22 judges before anyone is appointed from the January competition.

The High Court had an 'unprecedented' number of unfilled vacancies this year. Eight judges were recruited in an exercise to fill 14 posts. Early High Court retirements have significantly increased.

The situation has become so bad that the review body considered recommending outside the 1% pay norm. 'However, before we could report, the Ministry of Justice notified us of the government's own decision to put in place a new allowance worth 11% of pay for some judges in the High Court in England and Wales. The government did not seek the independent advice of the SSRB on this matter,' the report states.

The circuit bench failed to meet its recruitment target for the first time in 2016-17.

The Judicial Appointments Commission said workload and the increasing number of litigants in person were also deterring potential applicants.

The LCJ is taking a 'cautious approach' to unfilled circuit bench posts. He believes application numbers may have fallen 'following developments in legal aid policy, or because criminal law solicitors and barristers were moving into more lucrative work'.

The JAC will be recruiting 300 recorders by February 2019. The commission had to apologise for the 'technical difficulties' experienced by nearly 2,500 applicants in February.

The report adds: 'The LCJ said London faced an additional pressure compared to the rest of the UK because it was the centre of the dispute resolution system and important in terms of the arbitration market. It was the location of a large number of international legal practices and the source of many alternative employment opportunities.'

The review body recommends all judges receive a consolidated 1% pay rise this year. It expects to complete a major judicial pay review by June 2018.