More than 5,800 victims of violent crime and sexual offences are stuck in one of the worst-ever backlogs in the crown courts, enduring delays of at least a year before their cases are heard, the Observer can reveal.

The number of cases facing these delays once a defendant has been charged has increased more than sevenfold in two years, according to an analysis of crown court figures in England and Wales.

Hundreds of lawyers have quit publicly funded criminal work, complaining legal aid fees are a “pittance”.

The backlogs in the crown courts may now worsen as criminal barristers are balloted on possible strike action later this month, which could include refusing new instructions and court walkouts.

The Observer has found:

* Crown court figures reveal that 5,849 cases involving violent crime and sexual offences have been waiting for more than a year to get to trial, compared with just 755 two years previously. More than 1,000 victims have been waiting at least two years.

* Some of the courtrooms at Snaresbrook in east London, the biggest crown court complex in England and Wales, were empty last week despite a backlog of 4,200 cases as it struggles with a shortage of judges.

* Victim support groups warn that some witnesses who are told their cases are postponed because of delays “just don’t bother coming back”.

The anonymous author of The Secret Barrister, which lays bare the failings in the criminal justice system, said: “The government wishes to present this as a grubby dispute about how much lawyers are paid – but it is about so much more. The reality is that the criminal legal profession is dying. My junior colleagues are struggling to make minimum wage – an average income of £12,200 a year – and the toll of working 80-hour weeks in a broken system is unsustainable. Delay is built into every part of the system.”

Jo Sidhu QC, chair of the Criminal Bar Association (CBA), said: “The evidence from the courts does not support the fantasy being fed to the public by ministers that delays are beginning to reduce. Each week, dozens of trials, including those for rape and other serious sexual offences, are being postponed at the last moment.”

Alex Mayes, from the charity Victim Support, said: “We have seen cases of victims where the emotional burden of the trial and delays have led to them dropping out, or they have gone through the process and come out of it feeling they would be unwilling to do so again.”

In evidence to a Commons public accounts committee inquiry into criminal court backlogs published earlier this year, one witness care unit in Lincolnshire reported 185 cases with no fixed date for trial. A second support service in the county warned: “The delays and subsequent adjournments, even when trials are relisted, are showing us that witnesses just don’t bother coming back and [the Crown Prosecution Service] is offering ‘no evidence’.”

The backlog was increasing before the pandemic and a key reason is cuts to the legal aid budget, which has fallen by 43% in real terms since 2004-05. According to the CBA, the number of junior barristers practising exclusively in crime declined by 11% from 2,553 in 2016 to 2,273 in 2020. The number of criminal legal aid firms in England and Wales has fallen from 1,861 in 2010 to 1,090 in 2021.

John McNamara, a criminal barrister who has largely stopped working on legal aid-funded cases because of low fees, said: “Barristers are voting with their feet and leaving criminal work. There aren’t enough skilled workers to help in clearing the backlog.”

Defence solicitors complain that fixed fees for advising defendants in police stations, including travel, correspondence and phone calls, have fallen over the years. The police station fixed fee for a defence lawyer’s attendance in Hartlepool was £131 in 2021, compared with £144 in 2008. The fixed fee for preparing for a two-day burglary trial is just £353.

Hesham Puri, president of the London Criminal Courts Solicitors’ Association, said: “The system is broken. We have got lawyers leaving and can’t recruit new ones. When I started, you would get about 100 CVs a month from solicitors and trainee solicitors. We don’t get any now.”

Kelly Thomas, a partner at Tuckers Solicitors, who is based in Brighton and has been a defence lawyer for more than two decades, said: “I’ve seen really good lawyers who have just said, ‘I’ve had enough.’ We say to the rest of the world that we’ve got this fantastic justice system, but it’s disappearing.”

The Ministry of Justice is working to reduce the backlogs but is hampered by a shortage of judges and advocates. At Snaresbrook crown court last Thursday, three of the 18 available courts were not sitting, despite staff facing the biggest backlog of cases in the country.

There are frequently not enough judges to sit in the available courts, or barristers may be engaged in other cases. Crown courts in Birmingham, Leeds, Manchester, Nottingham, Sheffield and Chelmsford all have backlogs of more than 1,000 cases.

The overall number of cases waiting to be heard in the crown court has increased from about 39,000 in early 2020, before the pandemic, to more than 58,000, a rise of nearly 50%.

A ballot for strike action by barristers on legal aid fees closes this evening and, if there is support for action, there could be court walkouts from next Monday. The CBA says the action is aimed at redressing the shortfall in the supply of criminal barristers to help deal with the crisis in the court. Ministers have agreed pay increases after an independent review by the former judge Sir Christopher Bellamy, but lawyers say they need an immediate pay rise.

Dominic Raab, the justice secretary, announced a new pilot scheme last week for specialist courts for rape trials to help reduce backlogs. Some rape victims are waiting five years from an offence being reported to a conviction.

A Ministry of Justice spokesperson said the outstanding caseload in the crown courts had fallen by 3% in the past year: “This is thanks to our decisive action and the hard work of legal professionals including criminal barristers, who, as a result of our proposals, will earn nearly £7,000 extra per year. This is a significant pay rise, and we encourage the CBA to work with us, rather than continue or escalate unnecessary disruption in the courts which will only serve to delay justice for victims.”