A network of 12 bells including ones on the coastline of Anglesey and Gwynedd are tolling a warning about rising sea levels.

The Time and Tide bells have been installed to warn of high tides which cause them to ring more and more often these days.

In Wales the bells are already in place at Cemaes on Anglesey and at Aberdyfi where legend has it the tolling of bells is all that’s left of the land of Cantre’r Gwaelod.

Legend has it that the fertile, low lying kingdom of was submerged forever beneath the waters of Cardigan Bay in the fourth century after the drunken guardian of the sea defences, Seithennyn, forgot to shut the sea gates because he had got drunk at a feast.

It was a stormy night and the high spring tides broke through, quickly flooding Cantre’r Gwaelod, and forcing its people to flee to the hills.

The enduring tale was immortalised in the song ‘Clychau Aberdyfi’ (The Bells of Aberdyfi).

The story of the bells, including another of them just off the coast of the tiny island of Bernera in the Outer Hebrides, is told in a major new three-part television series, Llanw (Tide), made by Caernarfon-based television company Cwmni Da.

The first programme in the series will be broadcast on S4C at 8pm on Sunday, 2 June.

The bronze bells are the brainchild of artist Marcus Vergette and are also intended to convey the threat of rising sea levels caused by global warming.

He said: “The sea both connects and separates us. Bells talk in celebration and loss and I thought that this new bell form that I have designed could respond to that complex relationship.”

Cwmni Da filmed on four continents, taking in 10 countries and the Arctic for the £600,000 series about the ocean’s tides.

On Bernera former fisherman Iain MacAuley, who helped install the bell there in 2010, has been back to Bosta beach to carry out repairs and he said: “The sea is in your blood. It never really goes away.”

As well as at Bernera and at Cemaes and Aberdyfi, Time and Tide Bells have also been installed at Appledore, in Devon, at Trinity Buoy Wharf, London, near the Meridian Line at Greenwich, and at Morecambe Bay.

There are plans for bells at Brixham, Devon, Mablethorpe, Lincolnshire, and Happisburgh, Norfolk.