David Grant, a chemistry teacher at Brecon's Christ College, sprung into action when he was told a woman had entered the Usk, near the independent school, at Llanfaes Bridge just after 6.30am.
He had been due to take pupils from the school, where he'd stayed overnight, swimming but instead fetched a kayak from the school's store near the river and offered his help to the police during the Wednesday June 3 incident.
"The police officer in charge said the fire brigade were waiting for their boat to arrive, so I got into the kayak," said David who has been trained in swift water rescue as a member of Brecon Mountain Rescue Team.
A fire and rescue crew pulled David and the woman from the water using ropes. The woman, who is in her 20s, was treated by paramedics and is understood to be recovering.
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