Ski Sunday presenter Chemmy Alcott says she suffered a collapsed lung after jumping into a lake while on holiday in France.

The 44-year-old former GB Olympic skier posted a clip on Instagram that showed her jumping off a five metre platform into Lake Annecy, in the French Alps, before landing badly and ending up in hospital.

“Most people badly time a front flip off a five-metre platform and get winded,” she said in the clip.

“I apparently don’t do things by halves. Collapsed lung, chest drain and a very expensive lesson in rotation.”

Alcott explained that she initially went back to jump again after her difficult landing, out of “embarassment” and “just so I wasn’t making a big deal out of it”.

But she soon realised she “couldn’t breathe properly and should probably go and get it checked out”.

She later shared images of herself in hospital with tubes and wires sticking out of her body.

In the caption to the main clip – titled “this didn’t end well” – she wrote: “Well… that escalated quickly. Turns out five metres is quite a long way to discover you’ve got the rotation wrong.

“One badly timed front flip. One very hard landing. One collapsed lung. One chest drain. And a few more hospital overnights than were on the holiday itinerary…

“I absolutely loved Annecy… but I’m not entirely sure it loved me back.”

A collapsed lung – medically known as a pneumothorax – occurs when air becomes trapped in the space between the lung and the chest wall, according the NHS.

In the UK, one of the main dangers of swimming in lakes is the threat of what is known as “cold water shock”.

That’s when cold water can cause a sudden heart attack by increasing your heart rate, or making you gasp for breath and inhaling water directly into the lungs, leading to drowning.

But the temperature in Lake Annecy in the summer is a balmy 25C to 27C.

Alcott’s injury is more akin to running into something very fast – technically known as a blunt trauma injury.

This is where the skin isn’t broken or pierced, but there can still be severe damage to bones, muscles, and internal organs – in her case a lung.

Having jumped off a five-metre board, she was probably travelling at around 20mph by the time she hit the water.

The injury will have been caused by her chest slamming into the water.

The Royal Life Saving Society (RLSS) urges summer swimmers to enter the water safely and look out for hazards.

“Is the area safe? Consider potential hazards – too deep or too shallow, currents, tides, underwater objects,” it says on its website. “Enter slowly and carefully, and never jump from heights.”

Former British champion Alcott raced in all five disciplines – downhill, super G, giant slalom, slalom and combined – during a successful career on the slopes.

She competed in her fourth and final Winter Olympics in 2014 in Sochi, then retired from international competition soon after on doctor’s orders, following several leg breaks.

Alcott joined the long-running magazine show Ski Sunday as a regular contributor and feature presenter before stepping up as its lead co-presenter alongside Ed Leigh in 2021.

Earlier this year, she covered the Winter Olympics in Milan and Cortina for BBC One.