A lawyer who was investigating the abduction and murder of a Cambridge University student in Cairo has himself disappeared - while en route to a conference to discuss state-sanctioned disappearances.

Ibrahim Metwaly was scheduled to fly to Geneva to address a UN meeting about forced disappearances and the case of Giulio Regeni, 28, who was carrying out research on Egypt’s trade unions when he disappeared on January 25, 2016.

Two weeks later his battered, tortured body was found dumped by the side of a main road outside Cairo, amid suspicions that he had been kidnapped and killed by the Egyptian security forces.

Regeni's personal belongings are displayed by the Egyptian Ministry of Interior

Mr Metwaly, who has represented the Regeni family as they push for the truth about what happened to their son, was last heard from when he spoke to his family on the telephone on Sunday morning.

There were reports that he was arrested at Cairo airport before he was able to board his plane.

He is the founder of a group called Stop Enforced Disappearances which aims to determine the fate of Egyptians who are “disappeared” by the security forces.

Mr Metwaly’s own son disappeared four years ago and has not been heard from since.

Italy has long suspected that Egyptian security agencies carried out the murder of Mr Regeni, who was a PhD student at Girton College.

Giulio, left, and Paola Regeni, the parents of Giulio Regeni, have condemned the Egyptian government's response credit: Ansa

The Italians have accused the Egyptian government of carrying out a sham investigation into the murder, and recalled their ambassador in protest.

But official protestations from Rome have been more muted recently and a new ambassador will be sent to Cairo this month.

Pier Antonio Panzeri, an Italian MEP and chairman of the European Parliament’s committee on human rights, said: "It is unacceptable that a prominent lawyer should vanish at an airport. I urge the Egyptian authorities to ensure the immediate and unconditional release of Mr Metwaly, a lawyer who is dedicating his life to denouncing this growing practice by Egyptian security forces of forced disappearances.”

Mr Regeni’s parents have said that his body was so badly tortured and disfigured that the only feature they recognised was his nose.

Aside from bruises, cuts and burns on his body, he suffered broken bones and shattered teeth.

The Egyptian authorities initially claimed that Mr Regeni had died in a traffic incident or that he had been the victim of a violent kidnapping – theories that have been roundly dismissed as preposterous by Italy.