Solicitors and probation staff begin a two-day joint walkout today in protest over the government's criminal legal aid cuts and plans to privatise most of the probation service.
Thousands of lawyers are expected to walk out across the country.
In London today the focus will be at Westminster Magistrates' Court. Tomorrow campaigners will gather in Westminster at 2pm before processing to the Ministry of Justice to wish justice secretary Chris Grayling 'happy birthday'.
Demonstrations will also take place in Manchester, Sheffield, Leeds, Hull, Liverpool and Birmingham.
The Law Society said it would 'support and respect' solicitors' decisions either to take part or work normally.
'We fully understand why some criminal lawyers have reached the point of despair after two decades without increases in legal aid rates, shrinking volumes of work and the MoJ's further cuts,' a spokesperson said.
Despite the deal done by bar leaders and the MoJ last week postponing barristers' fee cuts, many criminal barristers are expected to join the action, which could bring much of the criminal justice system to a standstill.
John Cooper QC, of 25 Bedford Row, told the Gazette: 'The majority of criminal barristers will support the solicitors' days of action. We continue in the rank and file of the bar to stand shoulder to shoulder with our solicitor colleagues.'
Criminal defence solicitors warn that under the new fee and contract arrangements two-thirds of legal aid firms will fail in the next year.
Probation officers argue that outsourcing the supervision of offenders to private and voluntary organisations is taking a gamble on public protection.
Nicola Hill, president of the London Criminal Courts Solicitors Association, said: 'What's 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.'
Said Hill: '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.'
Matt Foot, founder of the Justice Alliance, said: 'This is the first day in history when solicitors and probation officers have taken joint action.'
Meanwhile the Gazette has learned that the deal agreed between bar leaders and the MoJ to delay 6% cuts to Crown court fees until after the general election could be in jeopardy if barristers vote to continue protest action.
The Criminal Bar Association (CBA) is to ballot its 4,000 members over whether they want to accept the deal, agreed by the CBA leadership, executive committee and circuit leaders with the ministry to stop all protest action over the legal aid cuts.
If the vote, which will be held by electronic ballot, goes in favour of continued direct action, the 6% cut to advocates graduated fees (AGFS), which has been put off until next summer, could be introduced this year.
An MoJ spokeswoman said: 'The agreed package will need to be delivered in full by all sides.'
Barristers have been united with solicitors in protesting against the cuts, taking part in two walkouts.
Those that work in the Crown court have adopted a 'no returns' policy of not accepting work returned by double-booked barristers while many of those who do the very high cost cases have boycotted work since 30% fee cuts were introduced in December.
The deal, agreed without consultation with rank and file barristers has been met with widespread criticism.
Not all voices opposed Lithman's stance.
Max Hill QC, former CBA chair and head of chambers at London's Red Lion Chambers wrote to Lithman in advance of the decision advising him to accept the deal. Hill said: 'This is a remarkable climbdown by the minister and the government.
'Those close to the action must be aware how rare a victory this represents.'
Accepting the offer was not an 'abandonment' of solicitors, Hill insisted. 'Our solicitor colleagues have played a huge role in this fight. We must continue to support them and the referral system they represent.'
The shadow justice secretary, Sadiq Khan, said the protests illustrate the breakdown in relations between the justice system and the government.
'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.'