Constance Marten and Mark Gordon have been remanded into custody charged with manslaughter after a court heard the remains of a baby were found in a plastic bag under some nappies in an allotment shed.

The couple appeared at Crawley Magistrates’ Court on Friday accused of three charges – including concealing the birth of a child and perverting the course of justice.

Marten, 35, and Gordon, 48, spoke only to confirm their names, dates of birth and that they were of no fixed abode during a short hearing in front of a packed courtroom.

Gordon wore a grey jumper over his head throughout the hearing.

The aristocrat and her partner were charged with the offences on Thursday after the remains of the infant were found on Wednesday afternoon following a major two-day search operation.

The pair will appear at the Old Bailey on March 31.

Marten and Gordon were arrested in Stanmer Villas in Brighton on Monday after police attempted to establish their whereabouts over the course of several weeks.

A post-mortem examination is due to take place on Friday.

Detective Superintendent Lewis Basford, from the Met, previously said officers have been unable to determine the baby’s gender.

The case was referred to the police watchdog by the force, and the Independent Office for Police Conduct said in a statement that it is “currently assessing the referral to determine what, if any, further action is required from us”.

Remanding Marten and Gordon into custody, chairwoman of the bench of magistrates Carol Lintott said: “You are both here today… on charges of manslaughter, concealment of the birth of a child and perverting the course of justice.

“We are sending the case to the crown court sitting at the Old Bailey.

“We are remanding you in custody until that time.”