Passing through the countryside you would have little clue something quite extraordinary is being built nearby.

That is, until last week, when lorry-loads of concrete were delivered to the site of the new underground house.

After that, though, the subterranean property will be almost hidden from view.

The unique construction is the design of contemporary architect Richard – the man behind the celebrated Kent home Crossway on Channel 4’s Grand Designs – and his team at Hawkes Architecture.

Their aim is to create an underground eco-property so in tune with its surroundings that, once completed, it will be barely visible to passers-by, with the above-ground area restored to heathland habitat.

They also want the house to be sustainable – zero carbon in fact.

The project has been almost six years in the making, with the £1.1 million build now well underway.

Excavation works have taken place in what was a former quarry and concrete is due to be delivered this week.

Richard says the land on which it sits is a scheduled ancient monument site and therefore protected, but due to the careful design, it was granted planning permission in 2011.

“It would have been inappropriate to put in a big space ship-type building,” he said.

“The land used to be a quarry where they would excavate gravel but the hole was filled in with sand, which has now been removed.”

The four-bedroom house is known as a PPS 7 new-build and is being constructed using state-of-the-art environmental building materials and techniques.

Richard says it has been designed to hide away in the landscape with a bespoke underground garage and storage space, complete with car lift, to conceal everyday items such as bins, lawnmowers and vehicles.

But despite it being subterranean, it is anything but dark, he says.

“It is all on one level. It’s got two long wings with bedrooms in one of them and the living space in the other,” he said.

“Each of the wings comes off a big courtyard in the middle, divided into two by a central entrance tube.”

Richard says it is the large courtyards which help provide so much light.

“These terraced areas provide the home with plant beds for growing vegetables and culinary herbs,” he said.

“The sunken nature of the courtyards also helps conceal domestic furniture and prevent light pollution from the house at night.”

Being an eco-home, Richard is also quick to highlight the materials used to create the unique property, including crushed Whitstable cockle resin for flooring.

He said: “We’re using felled English chestnut for the interior wall cladding. It will be triple-glazed and have highly insulated walls.”

The house will also have combined heat and power-generating solar panels.

But the build and planning process has not been straightforward.

Two previous attempts to secure planning consent were unsuccessful, until 2011 when Canterbury council finally agreed revised plans.

This is despite a number of objections, mainly concerning the construction process and the large number of lorries expected to travel along the narrow lane to the site during the removal of 800 cubic metres of soil.

Others, however, backed the proposal, including Harbledown and Rough Common Parish Council. English Heritage also approved.

Richard says that half-way through the project, the previous owner, who lived next door, decided to sell the site.

But he says the new owner loves the design and will be hands-on, doing a lot of the interior work himself.

“Currently, we’re working on the shell and the core,” said Richard.

“We’ve got a March completion date for the project.”