Celebrity SAS: Who Dares Wins remains one of the toughest reality TV shows and this year is no different, with some of the stars getting some grisly injuries while taking part.

Not everyone completed the tough course either, with Torchwood star John Barrowman quitting after just two hours. The 15 celebrities — which include Strictly's Pete Wicks and Bianca Gascoigne — were flown to southern New Zealand where they took part in gruelling military winter training.

Reality star Marnie Simpson was forced to quit SAS: Who Dares Wins after one of her wounds on her breasts had opened up and got infected. Meanwhile, Rachel Johnson — sister of Boris Johnson — broke a rib during her time on the show.

Brutal Injuries on Celebrity SAS

Geordie Shore reality star Simpson had a breast uplift weeks before flying out to New Zealand for the tough show. In addition to her surgery, it had only been around 11 months since the reality star had a baby and she said her C-section (caesarean) was "still quite sore".

While starring on the show, Simpson said one of her wounds on her breasts had opened up and got infected. With the show's many water-based challenges, she said it only got "worse" and she made the difficult decision to quit Celebrity SAS.

"[The DS] really wanted us to stay but I think it got to a point where the mental side, it was affecting us," Simpson told Yahoo and other press. "It wasn't doing any good being there physically and mentally. This is just not the right timing. I thought it's doing more bad than good to stay.

"If I’d not had surgery and I'd not just had a baby, I definitely would have stuck it out, but yeah, one of my wounds on my boobs had opened up and it was infected. The more I was going in and out of the water, and then I wasn't drying my body, it was getting worse."

She added: "I love this show but I don’t think it's worth my health."

She went on: "It's frustrating because I feel like if I had more time and I would have mentally and physically prepared to go in there cos I definitely wasn't mentally right either. I just wasn't in a good head space. Physically, my C-section was still quite sore and my boobs were sore. It wasn't the right timing."

When she went down into a dam, she detailed she was left in "agony".

"Oh god that was awful," she said. "The pain that put on my C-section scar. I was in agony. Honestly, weeks after I left I thought I damaged my scar. My C-section scars were not ready. I had a bad delivery, that was just horrific."

Fellow SAS teammate Rachel Johnson said she was "absolutely horrified" Simpson was taking part in the show and that she felt protective of her like she was her daughter. "I'm surprised that production allowed you to do the show," she added.

Johnson also was injured while coming down the dam on day two of filming Celebrity SAS. The journalist, who previously appeared on Celebrity Big Brother, had broken one of her ribs. With doctors unable to do anything about broken ribs, Johnson made her own decision to "power on through" with the Channel 4 show.

"I broke a rib," she told press. "It was a lose-lose situation cos you're in terrible pain and you go to the doctor and you say, 'I can't walk or I definitely can't run. And I definitely can't carry my pack.' And the doctor says, 'Well, you know, there's nothing I can do about a broken rib. I'm not an X-ray machine. Do you want to leave?' So you just have to power on through."

Early Exits on Celebrity SAS

But it’s not just injuries that have forced some of the stars to quit. John Barrowman, best known for his roles in Doctor Who and Torchwood, left the show after just two hours, according to fellow contestant Rachel Johnson.

Johnson revealed to MailOnline: "John left like two hours in. He did the first day and then he voluntarily withdrew in camp. When we were doing the tour of the accommodation."

Barrowman's exit came after reports that dancing sensation Louie Spence also left the show early, after just 24 hours. According to reports, Spence had initially been excited to be part of the show, but found the grueling training to be too much for him.

Billy Billingham Labels One Star 'Worst of the Series'

Chief instructor Billy Billingham has revealed that one star on the show was the "worst of the series" after they quit after just 32 minutes.

Billingham, who is known for his tough but fair approach, told The Sun that he was "disgusted" by the star's decision to quit so early on.

"I make every one of them cry," he said. "I can't talk about this because it hasn't come out, but you'll see when the next one comes out... There's a certain person on there, which I was just... I couldn't believe it.

"I was like... really?

"You have a chance here to do so many great things and you just can't be bothered."

"It's a man, just couldn't be bothered to, he didn't even get past day one. So there's your answer," he added.

"You'll see him. I was disgusted, absolutely disgusted, to be honest, you know. So that was my worst one.

"I can't say and I want to say it so bad but you'll see."

Celebrity SAS: Who Dares Wins Returns to Channel 4

Celebrity SAS: Who Dares Wins is back on Channel 4 on Sunday, September 22. Get ready for more grueling challenges, dramatic exits, and plenty of tears as the new recruits face their toughest test yet.