A post-mortem examination held on 3 March was not able to establish a cause of death and further tests will take place.

The child's body was found wrapped in a plastic bag under some nappies in an unlocked shed near to where Constance Marten and Mark Gordon had been camping on an overgrown allotment plot in Brighton, Crawley Magistrates' Court was told.

The details were revealed during the pair's first court appearance on Friday, during which a charge that they "unlawfully killed baby Victoria" was read out.

Marten, 35, and Gordon, 48, are also accused of concealing the birth of a child and perverting the course of justice.

Gordon was pictured in handcuffs exiting a prison van, flanked by guards, before the hearing.

During the short hearing, they spoke only to confirm their names, dates of birth and that they were of no fixed address.

The pair were refused bail and remanded in custody until their next court appearance at the Old Bailey in central London on 31 March.

They had been missing since 5 January and were arrested in Brighton on Monday - and charged in the following days.

On Wednesday, the Metropolitan Police had said they did not yet know the gender of the baby and that it "may have been dead for some time".

A post-mortem examination is due to be carried out today to discover how the newborn died.