Criminal solicitors and probation officers have begun 48 hours of industrial action in protest against cuts to legal aid and the privatising of offender rehabilitation services.
The combined demonstration against Ministry of Justice policies is aimed at bringing the criminal justice system in magistrates and crown courts across England and Wales to a standstill.
Despite criminal barristers settling their differences with the justice secretary, Chris Grayling, last week, solicitors who conduct criminal defence and prosecution work are persevering with their mass walkout.
The protests are the third time this year that lawyers have taken direct action over MoJ plans to slice £215m out of the department's annual budget for legal aid. The Justice Alliance - a coalition of charities, unions and community groups that including Liberty, Unite, The Howard League for Penal Reform and Coram Children's Legal Centre - is supporting the demonstrations.
It warns that imminent changes to judicial review will also have a chilling effect on challenging poor government decision-making, leading to a situation of state impunity.
Probation officers planned their strike some time ago. They will start their walkout at midday on Monday. Ian Lawrence, general secretary of the National Association of Probation Officers, said: "The government plan to outsource 70% of the probation service is untried and untested.
"It is a dangerous social experiment that we believe will lead to a reduction in rehabilitation and fragment risk management, placing the public at risk. These reforms are ideologically driven and being pushed by a political timetable."
Nicola Hill, president of the London Criminal Courts Solicitors Association, said: "What is happening to probation and criminal legal aid belongs to the same sorry story. That's why criminal defence solicitors are standing by colleagues in probation.
"As the government dismantles the criminal justice system, risks are being taken which threaten public safety and the right to a fair defence. The MoJ is taking a gamble on outsourcing the supervision of the most persistent offenders on release from short-term prison sentences.
"Meanwhile as the justice secretary scrimps on legal aid, the risk of the innocent going to jail is set to become a nightmarish reality. Miscarriages of justice for ordinary people will increase because they can't get a decent lawyer."
Some barristers threatened to support the action despite the deal reached last week. Henry Blaxland QC said: "I and other barristers support the protests on the 1 April.
"The Criminal Bar Association ignored calls by many of its members for support for the solicitors' and probation officers' days of action and, instead, did a deal with Grayling, without consulting the membership. We shall continue to unite for justice and together will fight to oppose cuts to legal aid."
Matt Foot, of the Justice Alliance, said: "This is the first time in history when solicitors, barristers and probation officers have taken joint action not to work the courts. All but the rich will suffer because of these cuts - which is why we are united and determined to stop [Grayling]."
Demonstrations are expected outside courts. The largest on Monday will be outside Westminster magistrates court. On Tuesday 1 April - which is also the justice secretary's birthday - a rally will be held outside parliament followed by a march on the Ministry of Justice.
Labour's shadow justice spokesman, Sadiq Khan, said the protests were "a clear illustration of just how much relations between those working in the justice system and the government have deteriorated. Dedicated professionals concerned at keeping the public safe and maintaining access to justice have lost confidence in a justice secretary who has shown, at best, a casual regard for our courts and probation service.
"We urgently need all sides to work together to see if progress can be made to avoid irreparable damage being done to our justice system."
The MoJ maintains that the UK's legal aid budget of about £2bn a year makes it "one of the most expensive legal aid systems in the world", and insists it will "remain very generous even after reform".
Grayling said last month: "This government is dealing with an unprecedented financial challenge and I have no choice but to look for the savings ... I cannot exempt legal aid but that doesn't mean I don't understand how challenging these reductions will be. The final package does mean fee reductions, but it also includes a series of measures to ease their effect on lawyers."