The legal action was launched yesterday more than five-and-a-half years after the Jamaican illegal immigrant collapsed when she was bound and gagged by police as she resisted a deportation order.
At least 13ft of tape was wrapped around her head to gag her, her hands were cuffed and belts tied around her waist, legs and ankles. Mrs Gardner, 40, collapsed after the struggle and died four days later in hospital on 1 August, 1993. Three police officers were cleared of manslaughter at the Old Bailey.
Mrs Gardner's son Graeme, then aged five, was in the flat at Crouch End, north London, and was deeply traumatised by seeing his mother die, according to the family's solicitor, Louise Christian.
Mrs Gardner's mother, Myrna Simpson, who now cares for Graeme, is also claiming damages. She said: "It has been a long battle to get justice for Graeme for his mother's death and I hope justice will now be done."