A former Royal Marine who sexually assaulted a woman after years of harassment has been warned he faces a long jail sentence.
Glyn Jones was due to be sentenced at Exeter Crown Court but his case was adjourned to allow his defence team more time to investigate the background to the offences.
Jones is a former Royal Marine who once claimed he was part of an elite surveillance team that spied on Princess Diana.
He had been harassing the victim for years and had threatened to sexually assault her and to kill her, Exeter Crown Court was told.
Jones, aged 61, of Berry Close, Exmouth, pleaded guilty at an earlier hearing to one charge of assault by penetration which dates back to November 19, 2012.
Judge Francis Gilbert, QC, remanded him in custody after hearing that new victim impact statements increase the seriousness of the allegations against him.
He gave defence counsel more time to prepare his mitigation in the light of the new information.
Mr Andrew MacFarlane, prosecuting, said:"This was not an isolated incident. It was the culmination of a considerable period of extraordinary psychological harassment by the defendant.
"This did not happen as a momentary offence but at the end of a long campaign in which he made threats against the victim.
"In her first statement she described threats going back to 2008. He told her he would do two things. She says he carried out one of the threats and the other one was that he would kill her."
Judge Gilbert said:"This is a very serious offence which is going to result in a lengthy sentence measured in years rather than months. It is not in the public interest that the defence should be rushed."
He said there was no point in obtaining a psychiatric report because it was unlikely to affect the sentence. Jones, who served 22 years in the Royal Marines before leaving in 1993, is said to be suffering from post traumatic stress disorder.
Mr Brian FitzHerbert, defending, said he hoped to draft a basis of plea before the final hearing next month.
Jones made headlines all around the world in 1994 when he revealed he had been part of a secret surveillance team who monitored Princess Di's movements to ensure her safety.
He said he had hidden in undergrowth close to the back garden of her lover James Hewitt's then home in Ebford, near Exeter, and seen them having alfresco sex.
He has featured in newspaper articles around the world more recently in which he has supported theories that British special forces may have had some role in the Princess' death in 1997.
