A British explorer has spent 11 nights completely alone as a castaway on the island formed by the volcano Hunga Tonga, which appeared in the Polynesian archipelago at the start of 2015.

Millionaire Ian Argus Stuart, 65, has now left the island along with incredible photos showing life there before it disappears back into ocean.

hunga tonga volcanic island
Docastaway

He was the first human to sleep on the remote land and spent the time camping in a cave, exploring the island and eating squid and seagull eggs.

In an interview with IBTimes UK, Stuart said staying on the island is a "unique feeling" because as well as being completely isolated, he knew it could sink back into the sea at any time.

hunga tonga volcanic island
Docastaway

"I never saw another boat nor boat lights at night, but I never felt lonely – probably because I have spent so much time in deserts and jungles around the world," he said.

Stuart arranged his visit with Docastaway, a company that provides holidays and experiences in remote desert islands around the planet. Should the island not disappear, the company hopes to use it in the future as a destination for wannabe castaways.

hunga tonga volcanic island
Docastaway
hunga tonga volcanic island
The volcanic island created by Hunga Tonga. 2015 CNES/Distribution Airbus DS

Although the island has not been named by Tonga officials (because it will probably not remain), Stuart dubbed the island Nuria, meaning God's Fire.

Explaining what the island is like, he said: "If you can imagine a lunar landscape, that is what the island is. Although it may look like rocks in the pictures, it is actually compressed lava dust and grit, so crumbles very easily. There are no real words to describe that place but it must be just like it was at the start of time."

hunga tonga volcanic island
Docastaway
hunga tonga volcanic island
Docastaway

He added: "But at least it doesn't suffer from the pollution of the cities – it has a very fresh clean ocean breeze smell about it.

"It's amazing how quickly plant and other forms of life establish themselves on a new island. You can see green shoots growing up from the lava grit along with many seagulls laying eggs there. I also spotted three butterflies and one spider."

hunga tonga volcanic island
Docastaway

Stuart has an agreement with Docastaway that if they spot any islands they would like scoping out, he is willing to go and visit them. He said: "It has worked out well for all concerned. I could never manage the paperwork involved and they get pictures of risk-filled islands that are not just staged for television."

During the 11 nights, Docastaway stayed in contact with Stuart through satellite phone and a team was on standby in Tongatapu, Tonga.

hunga tonga volcanic island
Docastaway

Stuart said he sheltered in a cave and stayed there until the sea damaged it. He said: "The island is disappearing day by day into the sea. The lake is not a lake anymore as the crater and the sea have joined together."

The island was half a mile long and is made mostly of ash. The eruption at Hunga Tonga began in December 2014 but a few weeks later, experts said it would be gone within the space of months because of its weak composition.

hunga tonga volcanic island
Docastaway
hunga tonga volcanic island
Docastaway
hunga tonga volcanic island
Docastaway