Captain Harpreet Chandi, 33, is 67 days into a 1,100-mile trek in Antarctica.

She wrote on Instagram: "Polar Preet has broken the world record for the longest, solo, unsupported and unassisted polar expedition by any woman in history!"

Team Army, a body that funds military sports, confirmed the feat.

The British Army medical officer, who was appointed MBE in the 2022 Birthday Honours, reached the South Pole for a second time earlier this month.

She has travelled 868 miles (1,397 km) so far in temperatures as cold as -50C (-58F), skiing 13 to 15 hours a day pulling a sledge, which she prepared for by training in Greenland and Norway.

The previous female record was 858 miles (1,381 km), skied by Anja Blacha in 2020.

Capt Chandi, a physiotherapist from Sinfin in Derby, failed to achieve her original aim, however, of becoming the first woman to cross Antarctica solo and unsupported.

After setting off from Hercules Inlet in November, her aim was to reach Reedy Glacier within 75 days.

In an online journey blog, she admitted on Thursday that she "pretty gutted that I don't have the time to complete the crossing".

She added: "I know that I have done a huge journey, it's just difficult while I'm on the ice and I know it's not that far away."

She called it "a tough day today" and said listening to recorded messages from friends and family had helped keep her spirits up.

"I have not yet located the Easter bunny or the tooth fairy, but I still have a couple of days left," she joked.

The Prince and Princess of Wales were among those to congratulate her, retweeting the announcement.

Astronaut Tim Peake commented on Instagram: "Awesome news. Congratulations Preet."

The University of Derby, which awarded her an honorary degree, and the Ministry of Defence also praised her achievement.

Capt Chandi, who is based at a Regional Rehabilitation Unit, helping injured soldiers with training and rehabilitation. She first made history trekking to the South Pole in 2021.

A GoFundMe page has raised more than £10,000, half of which will go to an "adventure grant" for females conducting "unique challenges", while the other will go towards Capt Chandi's next expedition.