A British convicted criminal who converted to Islam was jailed for three years on Monday for plotting to kill Prince Harry, the AFP news agency reported.
Ashraf Islam, 31, said he had a "moral right to judge" the royal because he fundamentally disagreed with the work of the British military, of which Prince Harry is a member.
The judge at Isleworth Crown Court in London described Islam's plot as "vague and unlikely to succeed", but said he presented a risk to the public.
Islam pleaded guilty in May to making a threat to kill the prince, the younger son of heir to the throne Prince Charles and younger brother of Prince William.
He had earlier handed himself in to police and volunteered the information about the plot, defense counsel Roxanne Morrell said.
In 2013, Islam admitted to threatening to murder the prince. Police searched Islam’s laptop and found that he had visited terrorist websites.
Judge Richard McGregor-Johnson said he would not go over details of Islam's plot, but told the court during the brief hearing, "This was not a threat made in isolation.
"The examination of your computer revealed you conducted research on his (Prince Harry's) whereabouts and intentions.
"You had given the matter considerable thought," said the judge, according to AFP.
The judge noted that police would have intervened had Islam, who has previous convictions for dishonesty and for involvement in an attempted robbery, attempted to carry out his plan.
Harry has served two tours of duty in Afghanistan but last month he gave up flying army helicopters to take up a desk job in the military.
In 2012, the Afghan Taliban vowed that it would do everything in their power to kidnap or assassinate Prince Harry.
Taliban spokesman Zabihullah Mujahid said at the time that the Taliban had a "high-value plan" to get the prince. "It is not important for us to kidnap him," he said. "We will target him and we will kill him."