The Justice Alliance is holding a day of protests around Britain on Tuesday of next week in defence of legal aid.
Demonstrators in London are set to rally at 4.30pm outside the Old Bailey with speakers including Shami Chakrabarti of Liberty, Raphael Rowe of the wrongly jailed M25 three, and the mother of a rape survivor.
Tory justice secretary Chris Grayling wants to slash £200 million from legal aid in criminal cases, on top of the £300 million already gone from civil cases.
Two thirds of law firms would perish and only people rich enough to hire their own lawyers would get to choose representation.
Poor people who end up in police stations or in court could be represented by firms such as Tesco, Eddie Stobart and G4S.