The delay occurred because the Home Office pathologist who conducted the official examination - which concluded that Mrs Gardner, 40, died from oxygen starvation - was unable to be present yesterday. It is normal practice for the pathologist who carried out the original examination to attend.
A third post-mortem examination is also due at about the same time, on behalf of the three suspended police officers at the centre of the affair.
Bernie Grant, the Labour MP who is acting on behalf of Mrs Gardner's family, said last night that he was 'very suspicious' about the delay. 'Clearly, in matters like this it is important for the post-mortem to be carried out as soon as possible. I intend to try and bring pressure to get it conducted more speedily.'
Mrs Gardner's body is at the Whittington Hospital, north London, where she died on Sunday after being on a life-support machine for five days.
Scotland Yard yesterday refused to comment on a report in the Independent and public statements by Mrs Gardner's mother, Myrna Simpson, that police officers had placed adhesive tape across her daughter's mouth in addition to using a restraining body belt with handcuffs.
Other police sources suggested yesterday that the use of tape could have been justified on the grounds that Mrs Gardner bit, or attempted to bite, the officers and that they feared she might be HIV-positive.