Who is Simon Charles Dorante-Day?

* 53-year-old British national who believes he's love child of Prince Charles and the Duchess of Cornwall.

* Claims his parents adopted him when he was 18 months old.

* In an interview with Today Tonight, Mr Dorante-Day said his family had no other connection to the British Royal family. But says his grandmother met his grandfather while they worked as a cook and a gardener for the Royal family.

Why was he in court?

* Mr Dorante-Day wants the court to help him return to work after he was suspended from his job with pay in June 2018 for allegedly threatening his boss while discussing leave balances.

* In a written complaint, Mr Dorante-Day's supervisor alleges the radio-electrical engineer made him feel threatened when he said: "that if I wanted to get into a driverless car heading for a cliff, then I would go over the cliff".

* Mr Dorante-Day is alleged to have also told his supervisor he was being watched by authorities investigating "the royal issue".

* He unsuccessfully appealed the Public Service Commission's decision to suspend him from work at the Public Safety Business Agency.

* He represented himself at the trial.

* He argued, unsuccessfully, that the public service had acted unconstitutionally and he had not received natural justice because there was a lack of evidence and due process wasn't followed.

What does any of this have to do on his claim of Royalty?

* Mr Dorante-Day told the court his "royal issue" had caused problems with colleagues.

* Said it was a contributing factor to him being suspended.

* Interviews he had given to New Idea magazine about his royal beliefs were an issue, he said.

Will this decision by the Queensland Supreme Court on Tuesday end his legal battles?

* No.

* Mr Dorante-Day previously told AAP he planned to file a case with the Federal Court over his claims of being a love child when he was back at work.

* Said he faces another concurrent suspension from his job which he plans to fight at the Queensland Industrial Relations Commission.

SOURCES: Mr Dorante-Day, Today Tonight, New Idea.

Australian Associated Press