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 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, June 2.

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.

It  is a first ever collaboration between Celtic language channels S4C, TG4 in the Republic of Ireland, BBC Northern Ireland and MG Alba in Scotland as well as LIC, the largest independent television production company in China.

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.”

Iain added: “On Bernera the community are very happy with the bell. At first they thought it would be a very loud bell that would be deafening everyone on the beach and waking the dead in the churchyard.

“When they saw it wasn’t going to be that noisy they were quite happy about it.”

Alasdair McLean, a Gaelic speaker from the Isle of Lewis now based in Inverness, directed the film about the Bernera bell and he said; “We had to plan the filming quite carefully because Iain could only go out to work on the bell at low tide and then we wouldn’t know if the repairs had been successful until the next high tide.

“It’s a very eerie place and it’s very connected to the sea from Viking times on to the present and even today fishing is a still a big employer on the islands.

“It just shows that even from King Canute’s day we still can’t really control the tide.

“It was a great project though and sometimes we’d be working with Welsh crew members and directors and that was wonderful because we’re Celtic cousins after all with our own language channels.”

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.

The Welsh, Irish Gaelic, Scottish Gaelic and English versions of the series have been edited at Cwmni Da’s state-of-the-art production centre where the voice overs were also done.

The series is being distributed in Greater China, Hong Kong and Macau and Taiwan by LIC and it’s hoped it can also be sold to other broadcasters world-wide.

Dylan Huws, the managing director of Cwmni Da, said: “Cwmni Da was the driving force of the project in many ways and we sent teams as far afield as China, Canada and Korea along with various locations in Wales and across the UK. In all we filmed on four different continents, including 10 countries and the Arctic.

“The production was epic in scale and content because we witnessed the world’s strongest and highest tides and experienced raging whirlpools and tidal bores in some of the most stunning locations on the planet.

“The highest tides are in the Bay of Fundy in Canada where they reach 70 feet, with a massive tidal range of 56 feet, the height of a five-storey building, between high and low tide.

“The largest tidal bore is in Hangzhou Bay in China and that was amazing.  There were 100,000 people on the banks of the river celebrating the annual Harvest Moon festival and witnessing the arrival of the tidal bore called the Silver Dragon which travels at 20 mph and is a bit like a tsunami coming up river.

“We filmed the world’s strongest tide in Norway in a fjord which squeezes the water in the outgoing tide through a 130 metre gap to the open sea and has claimed the lives of 60 people over the years.

“We have focused on human stories, so that you get a slice of people’s lives as well. For example, we looked at the way that people in China produce seaweed and at the work of the mussel fishermen in the Menai Straits.

“One of the most remarkable things we filmed was an amazing horse race which happens in Omey Bay in Ireland.

“They set up a horse racing track when the tide goes out and it only happens on one day a year.

“All the partners are proud of the fact that we have worked together because the television budgets for minority indigenous languages are challenging.

“This collaboration means we have all got more bang for our buck and created a great television series in the process.”