The kidnapping of a British model in Italy may have been faked as a publicity stunt, a lawyer for one of the men suspected of carrying it out has told a court.

The claim was made on Monday during extradition proceedings against Michal Herba, who is wanted by Milanese authorities in relation to the allegations. His brother, Lukasz Herba, is in custody in Italy.

“There is a real risk that the entire case is a sham,” Michal Herba’s lawyer told Westminster magistrates court on Monday. During the hearing, George Hepburne Scott called into question the reliability of the model, Chloe Ayling.

“The same complainant, it seems, generated publicity from the fact she was nearby the scene of a terrorist attack at the Champs Élysées in Paris,” he said. He also referred to claims that her alleged kidnapper in Italy had tried to tip off British newspapers.

Furthermore, Herba’s lawyer told the court about claims that the 20-year-old model and her captor went shopping for shoes, calling it a “wholly anomalous feature of a hostage situation”.

He said: “It would amount to an abuse of process of the court if there was any evidence to suggest this was a publicity stunt.”

Michal Herba is fighting extradition, having been arrested by the National Crime Agency (NCA), which was acting on a European arrest warrant issued by the Italian authorities last month.

On Monday, the prosecutor, Florence Iveson, said the 36-year-old had been requested by the court of Milan in relation to a single offence of kidnapping arising from events between 11 and 17 July.

“The allegation is that Mr Herba acted in complicity with his brother, Lukasz Herba, and other unidentified persons to kidnap the victim in Milan. It is said she was drugged and kidnapped and a €300,000 ransom was demanded.”

His 30-year-old brother, Lukasz, was arrested after taking Ayling to the British consulate in Milan on 17 July – six days after she was allegedly kidnapped.

The judge pointed out that much of the material relied on by Scott came from press reports, which he said did not prove any of the theories in the case. He is due to give his ruling on Friday.

During Monday’s hearing, Michal Herba – wearing a blue sweater and mauve tracksuit bottoms – limped to the witness box to be questioned over claims he has a heavily pregnant girlfriend in the UK.

His lawyers argued any extradition could breach his right to a family life, provided for by article 8 of the European convention on human rights. Herba refused to name the woman, citing his fear that she would be harassed by journalists.

Scott also said there was a lack of “particularity” in the allegations against his client, which refer to a “strong body of evidence”, including DNA samples, statements from the victim, and telephone wire taps.

He said the prosecution case did not set out whether his client was one of the men alleged to have drugged and kidnapped Ayling, or if he was said to have hired the car and the farmhouse used in the alleged offence.