The number of unrepresented defendants in criminal courts is increasing – but no one knows how big the problem is.

That is the conclusion of research published in a week when the lord chief justice complained that civil courts are having to abandon the adversarial system to deal with the increasing number of litigants in person.

Charity Transform Justice’s study, Justice Denied? The experience of unrepresented defendants in the criminal courts, says that while there are no authoritative statistics on the numbers of defendants lacking a lawyer, ‘the strength of perception of those working on a daily basis in the courts is compelling’.

Magistrates’ and district judges’ estimates of the proportion of unrepresented defendants in non-trafffic cases ranged from 15% to 40%. But the report’s author, former magistrate Penelope Gibbs, said the lack of data means unrepresented defendants in the magistrates’ courts ‘are invisible in policy terms’. Courtroom data on whether defendants were legally aided is ‘not systematically collected or collated’, she said.

Law Society president Jonathan Smithers said the means test income threshold of £22,325 is rendering thousands ineligible for legal aid but unable to afford legal advice, ‘leaving them no option but to represent themselves’. It is ‘deeply concerning’ that people are facing serious criminal charges without the support of a solicitor.

He called for the upper income limit for legal aid to be set at the 40% tax band.

Meanwhile, lord chief justice Lord Thomas of Cwmgiedd told peers that district judges in family cases are having to become ‘much more inquisitorial’ to cope with litigants in person. ‘It is impossible in a family situation to expect the adversarial system to work,’ Thomas told the House of Lords Constitution Committee.

Similarly, in the small claims courts, ‘there is much more of a judge moving nearer to an inquisitorial role,’ he said. ‘I think this trend is inevitable if we cannot equip the citizen to do it or the state will pay.’

Concerns about the role of McKenzie friends assisting unrepresented litigants in the family courts dominated the annual conference of family law body Resolution last week.