The 20-year-old former Tottenham youngster joined the Bees in September after impressing on trial but has not managed to break into the first team.
Youth boss Ose Aibangee told the club website: "We are not able to offer Josh anything further and we wish him all the best for the future.
"He is a good player and has every chance of a future in the game.
"We will do all we can to help Josh find another club. He has a good technical grounding from his time at Tottenham and has potential that can develop."
