Officers were called to the scene outside Whitehall School near Frays River at around 7.53am on Tuesday (January 3) after reports of a body in a river.
A post-mortem examination is due to be arranged in due course and no arrests have currently been made.
The death is being treating as unexplained.
A statement from the Met Police said: “Police were called to Cowley Road, Uxbridge at 7.53am on Tuesday January 3 to reports of a body in a river.
“Officers attended and recovered the body of a man.
“The death is being treated as unexplained.
“Enquiries continue and no arrests have been made.”
Whitehall School is closed today (Tuesday January 3) for teacher training.
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