A 35-year-old man suffered a swollen cheekbone after he was headbutted by a man in a black leather jacket.
The assault happened on the green between Willow Drive and Southwold School, Bicester, at about 5pm on Saturday.
Police described the attacker as white, stocky, about 6ft tall, and in his late 30s to early 40s. Anyone with information should call police on 101
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