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A couple who not only dreamed of living self-sufficiently, but faced eviction unless they did so, are the stars of this week's most unusual Grand Designs.

Their ambition was to create a comfortable three-bedroom home, a dream of many self-builders, but instead of a six- or seven-figure budget Simon and Jasmine Dale had just £500 in the bank.

The couple, with daughter Elfie and son Cosmo, joined the community of Lammas in Pembrokeshire to fulfil their desire to truly get back to nature.

Simon says: "We've been moving into this way of living for a decade. We're trying to follow our dreams, live a simple life."

Simon, a former photographer, and Jasmine, who worked in environmental education, were given a seven-acre plot by the Welsh Assembly on the condition that within five years they could prove they were 75 per cent self-sufficient - if not, they would be asked to leave.

The clause included producing their own firewood, shelter, managing their own waste, producing energy and, by no means least, running a small business.

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Simon and Jasmine Dale with Grand Designs presenter Kevin McCloud (Image: Channel 4)

Eight other families live on the hillside, none of whom had built their own homes before Simon and Jasmine started theirs because of the onerous demands of running successful businesses.

Grand Designs presenter Kevin McCloud says: "You might think this is just a bunch of hippies having fun on the side of a hill in Wales, but this is a research project and enshrined in government policy."

Before starting construction work, the family lived on the land in a one-room Hobbit-style house that Simon built and he admits their new home will be "medium-Hobbity".

After digging 12 feet into the hillside, they filled hundreds of sandbags - 7p each on eBay - with the earth they removed and built a retaining wall.

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Before starting construction work, the family lived on the land in a one-room Hobbit-style house that Simon built (Image: Channel 4)

One of the joys of living in an eco-village is that people from around the world descend on it to learn how to be self-sufficient and in return give their labour for food and shelter - the couple counted 277 people had helped them.

However, the first winter was so wet that work was held up for six months, and later Simon was forced to break off from the house to spend seven months building greenhouses so that Jasmine could start running a viable smallholding.

Later, Jasmine admits that the pressure of the self-sufficiency deadline had taken its toll and that she had had a "mini-breakdown", while Simon's sheer exhaustion had made him ill.

Grand Designs presenter Kevin McCloud says: "They're being asked too much. I think they're going to kill themselves."

The couple also had to raise funds through other work, with Jasmine running horticultural courses and Simon acting as a consultant on low-impact buildings.

However, they pulled through. The house has three bedrooms and a bathroom, complete with water-flushing lavatory which separates solids from the waste water - used for irrigation - while the solids are piped to a reed bed where they are dried and used as compost.

The round-pole timber frame is made from trees which Simon grew, felled, prepared and sawed himself, and the walls are filled with straw bales and coated in lime to help blend the house into the land.

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Almost all the materials were naturally produced on site, with the exception of a damp-proof membrane in the walls and on the turfed roof, and £2,000 of sheepswool insulation.

The windows and kitchen units were bought secondhand on eBay and even the floor - insulated by donated polystyrene granules made from packaging - is made of compacted soil, coated in linseed oil and polished with beeswax.

Four years went by and the deadline approached to prove that they were self-sufficient - after a long wait the council approved their business model and allowed them to stay.

The house, though still unfinished downstairs, is habitable and the couple estimate that it has cost them a total of £27,000 in materials - although the value of the vegetables they grew to feed the volunteers added £5,000 to the bill.

Kevin says he is "in awe" of the couple and their house - which is "21st-century in its comforts" - and concludes: "It's not just an example of how we could and should live, this is a clarion call."

Grand Designs is on Wednesdays at 9pm on Channel 4

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