Update 4.15pm: The Guardia Civil has confirmed, as anticipated, that the body is indeed that of the missing British windsurfer.
Update 8 March: Sadly, emergency services have announced that a fishing vessel has found a body in the sea near the Punta Rasca area. It is not yet confirmed that it is that of the missing British windsurfer, but it does seem likely. The lifeboat Una Salvamar is bringing the poor soul into Los Cristianos harbour at the moment, where the Guardia Civil are waiting to take control of the situation.
Update 7 March: The windsurfer missing since around 5.30pm yesterday afternoon is now said to be a 64-year-old British man. There is still no news about his discovery.
Original post 6 March: A search is underway this evening for a windsurfer who has disappeared off the coast of El Medano. Involved in the operation are a search and rescue helicopter, Protección Civil, Guardia Civil and the lifeboat Salvamar Alpheratz. The above photo has been released by the emergency services.