Hemp can be used to make everything from rope and paper to clothes and food
Cannabis' closest cousin is being used to build a home in Wales.
Although anyone caught growing cannabis could face years in prison, a similar and closely related plant is grown by the acre across huge farms in the UK.
Hemp, a variety of the cannabis plant, is grown specifically for industrial use.
Although cannabis as a drug and industrial hemp both derive from the same species and contain the same psychoactive chemical called THC, they are distinct strains with different uses.
The material can be used to make everything from rope and paper to clothes and food.
Hemp has much lower concentrations of THC than cannabis, meaning it has barely any psychoactive affects.
One housing builder in Aberdare is currently using the material to build a three-bedroom bungalow.
How do they do it?
After large bails of hemp arrive from a large farm in Yorkshire, the plant is mixed with a lime-binder in a similar process to concrete to make 'hempcrete'.
The wet-mix is then poured to fill walls, which creates an airtight structure meaning when you turn on the heating less escapes.
Builders fill the timber wall frames by hand and lightly tamp the mix, and often place shutter boards around the frames to keep it in place.
Avon & Co Building Consultants are using the product for the first time on one of their projects in Aberdare.
Hemp is being used to fill all of the external walls at the property which is currently under construction.
Co-founder Grant Avon, 40, from Aberdare, said: "It was my choice to use the hemp. When I was at university I learnt about its properties, and then with this build I suggested it to the client.
"It's a brilliant material. It's not incredible expensive, but it's not as cheap as some other more usual materials.
"It's also used as animal bedding - apparently the Queen uses it for her horses."
He added: "Nobody really knows how long it lasts. It was first developed [as currently known] in the 1980s in France.
"Over the past hundred years they had just been filling panels and walls with concrete, but that wouldn't allow the building to move and you'd end up with lots of air bubbles.
"But with this you don't get that as much, which means that your heating bills will be much lower."
According to research by a American building firm, a newly built hempcrete home was potentially more than 100% more energy efficient than traditional homes - which could see energy bills slashed by more than £1,000 a year.
According to latest Home Office documents, low THC cannabis grown for commercial production of industrial hemp is allowed if the grower has a licence.
Under the licence, parts of the plant which could be used for drugs must be lawfully disposed of.
Previously farmers were to put up screens around hemp being grown and make sure it was away from schools, public rights of way and troads.
But since becoming more widely used, the Home Office now ask grower to "site the crop sensitively".
Cannabis itself is a Class B controlled drug, meaning it is unlawful to possess, supply, produce, import or export this drug except under a Home Office licence.
It is also an offence to cultivate any plant of the Cannabis family, which includes hemp, except under a Home Office licence.
Hemp grown under a licence must have a THC level not above 0.2%, compared to typical cannabis in the UK which has an average level of around 14%.
Written by Thomas Deacon for www.walesonline.co.uk