The male European bison is vital to swell the numbers at the Wilder Blean project in the ancient woodland near Canterbury in Kent.

It is a joint project between two charities - Kent Wildlife Trust and Wildwood Trust - and "a privilege" to be part of, according to the latter's director of zoological operations, Mark Habben.

"It's brilliant to see these animals out acting naturally in this incredible landscape, but it's been a slog to get here," he said.

"It's been challenging - paperwork, veterinary matters, discussion with the EU just to try and navigate the movement of animals into the UK in a post-Brexit world, but we're here now and incredibly happy to be."

The three females were released into the woods five months ago and quickly and unexpectedly became four after it emerged one was pregnant - a surprise which left bison ranger Tom Gibbs "ecstatic".

"I'll remember it for the rest of my life - coming into work and lo and behold find this little baby calf alongside mum," he said.

"She started off like Bambi on ice. Now when you see her, she's looking like a proper little bison - she's strong, stocky and has probably tripled in size in three months."

Bison last roamed the country 12,000 years ago and nearly became extinct in the 19th century.

But the rewilding goes beyond securing the animals' future.

"We call them 'ecosystem engineers' and what they do is shape the world around them," Mr Gibbs said.

"All of the tracks they create, breaking trees, eating vegetation, dust bathing, give other species that are often less competitive space to grow and thrive."

And that, he explained, helps prepare for climate change.

"It allows the woods to adapt to a much more uncertain future by having a much more diverse set of species living in it. It means it's more resilient in the face of different temperatures," Mr Gibbs added.

Others want to follow suit and reintroduce bison.

But Merlin Hanbury-Tenison, the co-founder of Cabilla Cornwall, which has already introduced beavers, says the red tape is a major barrier.

"There are huge issues around the licencing with Natural England around fence specifications, around the feasibility studies, the stakeholder engagement, the inspection cycles that needs to be put in place," he said.

"It makes it incredibly expensive and incredibly onerous for anyone trying to do it."

A spokesperson for Defra, which sponsors Natural England and is advised by the organisation on environmental matters, said in a statement: "We have supported opportunities to reintroduce formerly native species where there are clear benefits for nature, people and the wider environment.

"We fully assess each application to ensure that all enclosures are secure and that potential impacts are carefully considered before issuing a licence."

At Blean, it's all panning out just as they'd hoped.

Now with a bull finally joining the herd, it's hoped it won't be long before there are more bison making their mark on the tranquil corner of the Kent countryside.