Thousands of cases were disrupted after the main court computer system went down at hundreds of courts across the country last month.

The chaos, during which trials were adjourned and hearings delayed, is an embarrassment for the Ministry of Justice, which is seeking to increase its use of online and digital hearings through its £1.2 billion court modernisation programme.

The failure meant that court files could not be retrieved, jurors could not be empanelled, and barristers could not register for attendance payments.

The Ministry of Justice issued an online statement apologising to those affected, stating: ‘We know this is unacceptable and how deeply frustrating this has been for our staff and users.’

Richard Atkins QC, the chair of the Bar Council, said: ‘I have no doubt that the Ministry of Justice and HMCTS are doing all that they can to rectify this major problem, but it illustrates how vulnerable the delivery of justice is with reliance on weak IT systems in our courts.

‘Whilst HMCTS is moving forward with its programme of online justice, these problems would suggest that more investment in the basics is needed first. We cannot have a justice system that comes to a shuddering halt the moment the IT does not work properly.’

Chris Henley QC, chair of the Criminal Bar Association, issued a statement which said: ‘Short-term savings often result in wider costs to the public purse and cause a broken criminal justice system to fall further apart. Crumbling court buildings are bad enough for court users – both the public and criminal practitioners – but digital failures can have far more profound consequences for all those awaiting trial.

‘Prolonged IT failures do a disservice to the victims of crime and their families who may have already suffered the costs of delays from an already overstretched, chronically underfunded, broken criminal justice system.’

Legal blogger and author the Secret Barrister tweeted to say: ‘The entire digital infrastructure of the courts has been broken for days. Phones aren’t working, court computers are offline, email is down. Imagine the headlines if it were the NHS. But it’s only justice, so no one cares. No accountability, no lessons learned.’

The justice minister, Lucy Frazer, was forced to attend the Commons chambers and apologise for the fiasco. She denied that the problems were caused by a cyber attack, and put it down to an issue  ‘caused by an infrastructure failure in our supplier’s data centre’. She said: ‘We are very disappointed that our suppliers [Atos and Microsoft] have not yet been able to resolve the network problems in full,” she added. Penalty clauses in the contracts with the suppliers could be invoked.’

Frazer told MPs that all judges would receive a personal letter from Sir Richard Heaton, the permanent secretary at the Ministry of Justice.

The Independent Group MP and barrister Anna Soubry said: ‘If we had a better, more fully funded system, there would be proper backups and this rumbling problem would have been sorted out a long time ago… The system is now reaching crisis point and funding is primarily a problem.’