Met Police have said that James Matthews, 43, will be formally charged with “attending a place used for terrorist training” when he appears at Westminster Magistrates’ Court on 14 February.
He is alleged to have attended “a place or places in Iraq and Syria where instruction or training was provided”, in relation to the commission or preparation of a terrorist act on or before 15 February 2016.
The offence is contrary to section eight of the Terrorism Act 2006 and is the first charge of its kind in the UK.
Many British men have travelled to Syria to fight IS with the YPG, which is mostly made up of Kurdish men and women, and a number of them have died in the conflict.
Oliver Hall, from Portsmouth, died while clearing mines in Raqqa in November, with others to have died including sniper Jac Holmes, 24, and Mehmet Aksoy, 32, who died in an IS attack.
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Ryan Lock, 20, shot himself to avoid being taken hostage and Luke Rutter, 22, Dean Evans, 22, and Konstandinos Erik Scurfield, 25, were all killed in operations against IS.
Matthews was among those featured in a Channel 4 documentary – Frontline Fighting: The Brits Battling Isis – in 2015.