Criminal law firms have indicated they will refuse legal aid-funded cases in protest against government cuts they describe as "untenable".
Solicitors' fees are to be reduced by a further 8.75% from today, bringing the total reduction to 17.5% following a cut by the same amount last year.
The Government has sought to slash the scheme's budget, which Justice Secretary Michael Gove said was "significantly higher" than other EU nations.
But representatives of criminal law practices warned of "very limited coverage" at police stations and courts after solicitors decided to take action.
Bill Waddington, chairman of the Criminal Law Solicitors' Association, wrote to Mr Gove to warn that barristers and solicitors in areas including Liverpool, Manchester, Cardiff and Birmingham had met to discuss refusing to work at the new rates.
He said: "Unity between solicitors and barristers, both silks and juniors, lead us to believe that from the 1 July there will be very limited coverage across the country in police stations and courts, and over a period of time the situation will deteriorate further.
"We know that individual solicitors who have come to this conclusion have taken this decision with a very heavy heart indeed.
"The criminal justice system is heading towards meltdown as a result of these cuts, and if we do not take this desperate action now access to justice will be decimated by your proposals with very many vulnerable and young people exposed to miscarriages of justice."
More than 100 solicitors and barristers met in Merseyside last weekand agreed the changes were "untenable", according to Zoe Gascoyne, chairman of the Liverpool Law Society Criminal Practice Committee.
She said: "The Government recognise that the profession is fragile and yet continue to take grave risks with the stability of the criminal justice system. The profession gathered today are deeply concerned about the impact of this upon access to justice.
"The message being delivered by individual firms was that they had made an assessment of the cuts that are to be introduced on the 1st July 2015 and in January 2016 and that they will not undertake work at this rate."
Last month, the Law Society criticised the Government for going ahead with plans to slash the number of contracts for legal aid solicitors providing 24-hour cover at police stations from 1,600 to 527.