A 19-year-old student has set a new record for the fastest journey from the coast of Antarctica to the south pole.

Parker Liautaud, who went to school at Eton, is the youngest man to have skied to the pole, having completed the expedition in 18 days.

The teenage environmental campaigner has been on three expeditions to the north pole, the first when he was just 15.

He said he had set off for the 561km trek on 3 December with two main goals: "The first was to undertake scientific research and collect data samples. And the second was to reignite the dialogue on climate change by creating a story that people can engage with and be a part of."

After reaching the pole on Christmas Eve, Liautaud said: "The whole journey is really a mental one, managing uncertainty and trying to figure out how to manage risk. It is really a big relief to know that we have done it."

The previous coast-to-pole speed record was held by Christian Eide from Norway, who made the trip in 24 days.

Liautaud said the most challenging part of the expedition, which he undertook with his companion Doug Stoup, was the "mental game" he had to play.

"It was difficult to really not see the expedition as one big countdown to the south pole,” he said.

“It was important to break it up in to manageable chunks. That is really the only way to get through – take it milestone by milestone.

"I am very lucky to have had the opportunity to do the expedition. I feel fantastic. It could have gone either way."

On his way to the pole, Liautaud stopped to collect snow samples and deployed a lightweight weather station to measure and transmit climate data.

He had attempted to be the youngest person to reach the north pole when he was 15, but his team had to evacuate just 24km from the end of their trip. He completed an expedition there a year later.

Liautaud said he hoped to spend Christmas Day sleeping, adding: "I have lost around 20 pounds and I've only eaten nuts and dried food for the last month. I am really looking forward to having my first proper meal.

"I know it will be the best feeling waking up on Christmas Day knowing I don't have to walk another 17 miles."

Liautaud is half French and half American. He is an ambassador for One Young World, an organisation for aspiring leaders.

He grew up in California but moved to London when he was nine.

After completing his bachelor’s degree in geology and geophysics at Yale in the US, he plans to continue with scientific research and do a PhD.

Liautaud hopes to be reunited with his parents and younger brother in London early next month.