Italy has placed under investigation five Egyptian secret service and police officials for their alleged involvement in the torture and murder of Cambridge University graduate Giulio Regeni.

Mr Regeni, who was studying for a PhD at Girton College, was researching Egyptian trade unions for his doctoral thesis when he disappeared in 2016.

The 28-year-old Italian’s battered body was found a week later on a highway outside Cairo, with a post-mortem showing he had been tortured to death.

His mother said his body was so badly disfigured that she recognised only his nose.

The Italian authorities have grown increasingly frustrated with the lack of cooperation from the Egyptians, who initially claimed the graduate had died in a traffic incident or that he had been the victim of a violent abduction.