Solid wood is also preferable to cardboard or other processed materials because less energy is needed to create them. And burial rather than cremation is recommended to avoid CO2 emissions from the furnace.

There are a lot of naturally-grown coffin products to choose from these days: willow, bamboo, seagrass and even banana leaves, but all until now have needed sealants or linings.

Thorley Smith – which supplies to funeral directors, not direct to families of the deceased – seems to have made a major breakthrough, if its nomination for an environmental innovation and environmental procurement award is anything to go by.

Mr Roby said: "The advantage of solid wood coffins is the obvious one: it's the natural, traditional material. A tree is absorbing carbon from the atmosphere so, if trees are sustainably sourced, then that means a solid wood coffin becomes carbon-neutral.

"There is no overall increase in CO2 as a result of burning it. However, burial of solid wood, like pine, without any inclusion of plastic, is still the most environmentally-kind way of the two methods of disposal of human remains."