IN spite of the 25ft, fully water-powered cuckoo clock standing next to him, Richard Pim may be the most impressive thing in Westonbury Mill Water Gardens.

A hydrogeologist who brought water to arid farmlands in Saudi Arabia and Nepal, Richard spent around three years designing and making, piece by piece, his latest engineering marvel.

Believed to be the only giant cuckoo clock in the UK, and the first in the world to run using water, the mechanism sends a three foot cuckoo out into the Pembridge sky to the sound of bird calls on the hour, every hour – well, almost.

“It’s gaining a few minutes every day at the moment,” explained Richard. The warmer weather apparently causes the water to flow differently through the system’s myriad pipes and tanks.

“But no-one’s setting their watches by it.”

Inspired by its Bavarian counterparts, the cuckoo tower is the latest of what Richard affectionately calls his “follies”.

“I wanted to make something that made people laugh,” he added as the cuckoo began to ‘sing’ – a combination of a traditional cuckoo call and a higher warbling song that rises from a series of whistles blown by air pressure.

His wife, Sally, takes a different approach.

“Three years for that,” she said, before adding “No, I think it’s amazing what Richard does, astonishing.”

The couple own and run the water gardens together, from an old grey stone milliner’s cottage that, when Richard bought it in the 1960s, was so overgrown that it was “thrown in as part of a deal for the surrounding fields”.

Fully fixed up by Richard, it is now surrounded by the water gardens, as well as an igloo made entirely of coloured bottles, Australian ferns hiding inside thermostat-controlled Portaloos until the weather breaks, and a 25ft stone tower that shoots water from gargoyles mouths.

All were designed and engineered by the man who just “likes to work out problems”. The stone tower, for example, features a bucket and winch system powered by a small miller’s wheel that Richard found in the house soon after he bought it.

“A garden needs some action,” he said. “I’d seen this system used to irrigate fields in India, and thought it would work.”

Here, the buckets transport water to the top of the tower where it intermittently gushes out of the gargoyles – one, hand-chiselled by Richard, is in his own caricatured image.

His latest project is also his most ambitious, requiring a specialist from Bucknell to help construct the clock’s oak frame.

The rest however, from copper piping to Guiness can counterweights, came from Richard.

“It would be great for kids to come and see the mechanism – to see how engineering really works,” he said.

Westonbury Mill, on the A44 between Pembridge and Kington, is open daily, 11am to 5pm, until September 30.