Scientists and fertility experts at Longleat Safari Park are attempting a world first IVF treatment to try to save a rhino subspecies with only three individuals left.

The three remaining northern white rhinos all live under armed guard in Kenya, and are too old to naturally reproduce.

So in a last ditch attempt to save the endangered subspecies, scientists have extracted eggs from three southern white rhinos, a more common breed, that are living at Longleat, to make the first test-tube rhinos.

The nine eggs extracted from female southern rhinos earlier this week have been transferred to a laboratory in Italy to mature, before they are are fertilised with southern rhino sperm to hone the IVF process, before it is attempted in the rarer northern species.

Jon Merrington, head of safari at Longleat, told BBC Breakfast on Sunday that scientists working together on the project across Europe will soon know if the initial stage of the process has worked.

“Rhinos are a two tonne animal,” he said.

“Even to extract the eggs is 1.5 metres inside the animal – it’s such a complicated procedure.”

If these eggs successfully mature, they will be mixed with rhino sperm and cryogenically stored, before female southern white rhinos, potentially those at Longleat, are given a course of hormones to prepare them for a 16 to 18 month pregnancy.

“This is a groundbreaking procedure,” Mr Merrington said, “creating an embryo outside a rhino hasn’t been done before.”

If all goes well, northern rhino sperm and eggs will be harvested from the remaining members of the species, but because there are limited amounts to extract from these animals, IVF in more common southern rhinos is being tested first.

And if they cannot make a pure bred test-tube northern white rhino, they will try to create hybrid animals from sperm and eggs of the two closely related species.

Mr Merrington said that without human interference driving them to the point of extinction, the two populations would have likely mixed anyway.

“What we’re doing here probably isn’t too far removed from what could have happened in the wild.”