LONDON — A former Syrian air force colonel is unfit to stand trial in a landmark British case charging him with three counts of murder as crimes against humanity for attacks on civilians in 2011, a judge said Friday.

Not guilty pleas were entered on behalf of Salem al-Salem, 58, in the Central Criminal Court after prosecutors accepted medical findings that his rare neurological condition was too advanced for him to enter a plea or face trial.

Justice Bobbie Cheema-Grubb said al-Salem will face a trial of facts next year on murder and torture allegations but he won’t be required to appear in court. The trial will determine whether he committed the acts but cannot result in a conviction because of his condition.

Al-Salem is the first person in the U.K. charged with murder as a crime against humanity under the International Criminal Court Act of 2001. U.K. law allows British prosecutors to bring charges for some international offenses, including crimes against humanity and torture, regardless of where they were committed.

Prosecutors said al-Salem was part of a Syrian Air Force Intelligence group that suppressed demonstrations in the Damascus suburb of Jobar when the government carried out a bloody crackdown during the Arab Spring uprising against former President Bashar Assad’s authoritarian leadership.

Al-Salem “was tasked with quelling civilian protests against the regime and the defendant ordered officers under his command to shoot protesters and he himself shot protesters,” prosecutor Emilie Pottle said at a previous hearing. “The murders were part of a widespread and systemic attack against the civilian population.”

Al-Salem, who appeared by a video link with an oxygen mask over his face, has a progressive and fatal motor neuron disease that has left him paralyzed in all four limbs with cognitive impairment and limited ability to communicate, prosecutor Tom Little said.

“The motor neuron disease is now advanced. In addition, there is associated depression, apathy and cognitive impairment as well as severely restricted speech,” Little said in reading out one doctor’s report. “The defendant is monosyllabic and only really understandable to close family.”

He is charged with murder in the deaths of Omar Al-Homsi, Nizar Fayoumi-AlKhatib and Talhat Dalal in April and July 2011. He faces a count of conduct ancillary to murder in the death of Mohammed Salim Zahrak Balik.

Al-Salem is also charged with torturing three other people as part of his official duties. Prosecutors said he was present and participated in interrogations when detainees were beaten, shocked and hung by handcuffs from a ceiling.