Ysgol Preseli in the foothills of the rain-soaked Preseli mountains has tapped into its own water source. Mr Lloyd is already thinking of ways to incorporate the school’s new well into the curriculum.

He said: “We might look at a commercial aspect where we could bottle water. Pupils normally set up enterprise companies as part of their studies and this would be one thing they could research to see whether it is feasible. Our school uniform is maroon, so we could look for a maroon-coloured bottle. Tvy Nant has a blue bottle, we could have Dv wr Preseli in a maroon bottle.”

The search for water was driven by the need to cut the school’s pound;7,000 annual water bill, which is double that of comparable schools.

The school’s governing body called in diviner Heddwyn Jones, owner of Carmarthen-based Water Well Drilling UK, to scour the grounds.

Mr Lloyd said: “Mr Jones told us that in his opinion there was a plentiful supply of water under the school. He used hazel sticks, they were amazing, you could see the stick curl back.”

The governors approached Pembrokeshire County Council with the idea and the authority agreed Mr Jones could drill for water there. Mr Lloyd said: “They drilled 220ft down and when they changed the drill it shot up 50ft out of the ground like an oil geyser.”

The 800-pupil secondary will be connected to its new filtered supply by September. The underground lake will supply 200,000 gallons a day, enough for the secondary school, the village primary and the local leisure centre, including its 25-metre swimming pool.