The Law Society said the record high proportion of ineffective trials across England and Wales will cause "unacceptable" delays for victims and warned government underfunding is a key cause.
Ministry of Justice figures show there were 598 trials listed at Sheffield Crown Court in 202, many having been transferred from Doncaster.
Of them, 26 per cent were classed as ineffective – meaning they had to be adjourned to a later date – up from 21 per cent the year before, and the most since records began in 2010.
Trials can be labelled as ineffective for many reasons, including the defence or prosecution not being ready, witnesses being absent or “overlisting” – which means some cases will only be heard if court time becomes available.
A further 37 per cent trials at Sheffield Crown Court last year were cracked – when the Crown Prosecution Service drops the case or the defendant pleads guilty – and 37 per cent were effective meaning the trial went ahead as planned.
Moving into this year there was further disruptions to proceedings following a flood at the crown court.
Of the 21,805 crown court trials across England and Wales last year, just 48 per cent were effective – the lowest proportion in a decade.
Meanwhile, the proportion of ineffective trials rose to 23% – the most since comparable records began in 2010.
The Law Society of England and Wales said victims are facing are "unacceptable" delays and some are being forced to wait years for justice, while potentially innocent defendants are also left in limbo.
Stephanie Boyce, President of the Law Society, said the coronavirus pandemic is one factor, but lack of capacity in the system is another.
She said: "Decades of underfunding and cuts mean there simply aren’t enough judges, prosecutors and defence lawyers left to cover the huge backlog of cases.
“Defence lawyers will continue to leave the profession in their droves, and we will no longer have a criminal justice system worthy of the name, unless the Government changes tack urgently.”
She said swift investment is needed across the criminal justice system to get it back on its feet.
The rate of ineffective trials varied significantly across England and Wales – from just 9% in Salisbury, to 39% in Isleworth, west London.
Jeffrey DeMarco, assistant director at Victim Support, said this suggests victims are facing a "postcode lottery" which needs urgently addressing. Sexual offences
He added: "We are seriously concerned that effective trials in England and Wales have reached these lows.
"These statistics, alongside long waits for trial and poor prosecution rates for some crimes, show that the justice system has serious room for improvement."
Of the 155 ineffective trials at Sheffield Crown Court last year, 55 involved alleged violent offences – the most common type.
This was followed by sexual offences (36) and robbery offences (12).
The MoJ spokeswoman added: “While the unprecedented impact of the pandemic has led to large numbers of court staff and counsel falling ill or being forced to self-isolate, our decisive action has kept justice moving."