Three fire engines and three fire rescue units were called to reports of a horse fallen in a canal on Packet Boat Lane, Uxbridge.
Station Manager Jackie McConochie, who was at the scene, said: "The horse and its rider fell into the canal after the animal got spooked. The man managed to climb out to safety but the water was too deep and the bank too steep for the horse to do the same.
"We only had one chance to help the horse out as it was beginning to get cold and exhausted in the water. Four firefighters in dry suits went into the canal and built a platform out of sandbags, which enabled the horse to climb out.
“Thankfully neither horse nor rider were injured and they both were able to leave the scene under their own steam.”
The Brigade was called at 1724 and the incident was over for firefighters at 1944. Fire crews from Hillingdon and Hayes fire stations attended the scene.