Trials face disruption across England and Wales on Friday as barristers and solicitors fight cuts they say will damage justice

Barristers and solicitors will attempt to bring the criminal justice system to a standstill on Friday in protest at the government's latest round of £215m cuts to legal aid.

Trials at magistrate and crown courts across England and Wales are likely to be abandoned or rescheduled as a result of the first full-day walkout staged by lawyers.

An escalation of the dispute follows confirmation last week by the justice secretary, Chris Grayling, that the money will be removed from the annual criminal legal aid budget and the number of duty lawyers' contracts reduced by a third. Legal aid fees will fall by on average 6% for barristers and 17.5% for solicitors.

Hundreds of high-street firms specialising in criminal defence work will be forced to close, solicitors say, creating "advice deserts" in towns and cities where defendants will be left without adequate legal representation.

The largest demonstration will be outside parliament where barristers and solicitors – many in wigs and gowns – will assemble and then march on the Ministry of Justice to hand in a modern copy of the Magna Carta, the 13th-century charter which first imposed legal restraints on executive power.

Rallies will also be held in Manchester, Birmingham and other cities. The Criminal Bar Association (CBA) expects up to 3,000 of its barrister members to take part.

Four of the 18 courts in the Old Bailey were empty on Friday, including court 12 where the phone-hacking trial is being held, though the judge told the jury this was because of an appointment he had at the sentencing council.

On Thursday, one barrister working at the central criminal court said he was furious with the email sent out by the Crown Prosecution Service telling them not to take part in the day of action.

He said it was not just legal aid that was being cut, but the returns system, which ensures another barrister will represent a defendant in need of legal aid when their case is dropped by a different member of that barrister's chambers.

As well as abandoning their own cases on Friday, barristers will refuse to accept returns.

Nicola Hill, president of the London Criminal Courts Solicitors Association, said: "These cuts mean that law firms will rapidly go to the wall in their hundreds, leaving people who can't afford to pay privately with only the crumbs of legal aid.

"Firms will sack experienced, more expensive solicitors, replacing them with those who are unqualified and cheap. This can only be damaging for justice. The solicitors who are still in business quite simply won't have the time, money or expertise to prepare cases properly."

Nigel Lithman, chairman of the CBA, said: "If these cuts are not addressed then the British justice system, which is held in such high esteem around the world, will cease to exist as we know it and the British public can no longer expect true justice to be delivered.

"It is simply expected that the Criminal Bar will accept cuts unparalleled in any other sector of the wider community. The Bar cannot and will not accept these unnecessary and crippling cuts and will continue to fiercely oppose them at every opportunity until our reasonable requests have been met with the appropriate levels of consideration."

Many high-profile trials, including the PC Keith Blakelock murder case at the Old Bailey, are expected to be postponed until next week because of the lawyers' action.

Among barristers, there will be interest in the course of action taken by the prime minister's brother, Alexander Cameron QC. He is head of chambers at Three Raymond Buildings, a set which participated in the last half-day stoppage in January.

The head clerk said the choice of whether to take part in this action was up to each individual barrister.

Lawyers have been careful to avoid describing the action as a strike because that would raise complex questions over their contractual obligations to the Legal Aid Agency. The Crown Prosecution Service in London has written to barristers warning them that they may lose state prosecution work in the future if they decide to join the day of action.

Criminal barristers say they are already being paid rates as low as £20 a day, once the hours of preparation, time in court and chambers' fees are included.

The CBA added: "They receive no holiday pay, no pension provision and no sickness or maternity benefits. The government's proposed cuts … come on top of the 40% cuts already applied since 1997."

"Criminal barristers will no longer be able to accept cases funded by legal aid as they will be financially unviable. Ninety-eight percent of criminal barristers have already said they will refuse to work at the reduced rates for complex murder, fraud and rape cases."

One alleged multiple fraud case at Southwark crown court has already been boycotted by barristers, leaving defendants facing the prospect of representing themselves. The attorney-general, Dominic Grieve QC, has been asked to provide legal advice to ensure the case can go ahead.

The MoJ maintains that the cost of legal aid is around £2bn a year and describes it as "one of the most expensive legal aid systems in the world". Both claims are disputed by lawyers.

In response to walkouts by solicitors and barristers, the MoJ has said: "We entirely agree lawyers should be paid fairly for their work, and believe our proposals do just that. We also agree legal aid is a vital part of our justice system – that's why we have to find efficiencies to ensure it remains sustainable and available to those most in need of a lawyer."