Race Across the World: Cathie and Tricia's special friendship

Tricia (left) and Cathie have been friends since they were 13-year-old schoolgirls in mid Wales

From Thelma and Louise in the movies to the Absolutely Fabulous Patsy and Eddie, female friendships have been charming audiences for decades.

But there's a new couple of bosom buddies who have captured the hearts of many - Cathie and Tricia from BBC 1's Race Across the World.

Cathie Rowe, 50, and Tricia Sail, 49, who have been best friends since they were 13, spent 51 days travelling 9,942 miles (16,000km) from west to east Canada.

With a budget of just £2,498.13, and no access to phones or flights, things could have become tense - but they say there was barely a cross word.

Cathie says she and her best friend Tricia have a "wonderful friendship"

"Our friendship is very difficult to describe to other people," Cathie told Breakfast on BBC One.

"It is very natural to us, we don't really think anything of it but other people tell us how special it is and how unique it is.

"It is a wonderful, wonderful friendship and we can be completely ourselves with each other without worrying what the other one thinks."

The pair, who met at school in Aberystwyth, Ceredigion, spent much of their time in Canada holding hands.

Cathie (left) and Tricia have been friends since they were 13

"Cathie was literally my guide," explained Tricia, who now lives in Exeter, Devon.

Tricia has a degenerative eye condition and was keen to take on the challenge while she still could.

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At the time of filming she had about 10% sight in each eye, which has since deteriorated further.

"I will lose my sight completely," she said. "I wanted to do it to prove to myself and to other people that have sight loss that you can still live, you can still do all these things.

"Doing this journey with Cathie was just incredible because I know when we grow old disgracefully she's going to be able to say to me 'you remember the Rocky Mountains, it looks a bit like that'."

Cathie says the pair did not have a cross word during the challenge

Cathie, who now lives in Bridgend, said she was incredibly proud of her friend.

"She showed enormous strength, fantastic determination and she didn't let anything hold her back," she said.

"She quite often jumped in with both feet and I had to reel her in a bit - she was just incredible and I'm hugely, hugely proud of her and to be her best friend."

The pair met when they were teenagers

Despite the gruelling challenge and being far away from family, friends and home, Cathie insists they did not argue.

But there must have been things that annoyed them about one another?

Tricia's most annoying habit is reacting without thinking, said Cathie.

"It could be anything and she would just jump in there straight away without thinking about it and sometimes I'd be like 'well you do it then'".

The gruelling challenge saw the pair spend 51 days travelling thousands of miles from west to east Canada

And Cathie's most annoying habit?

"She has to think about things for a long time before she does anything," said Tricia.

"The perfect balance," said Cathie.

Tricia (right) has a degenerative eye condition and will eventually completely lose her sight

Spoiler alert - the pair won the series, taking home £20,000.

Since then they have been inundated with interview requests and seen their followers on social media rocket.

Tricia believes the interest in them is down to their relationship.

"I think it's that myself and Cathie have got such a good friendship, such a good relationship and we're not frightened of anything, I think that's why people have got behind us," she said.

The pair are already planning another trip together, this time walking the Great Wall of China

Looking back on the incredible adventure, Cathie has nothing but gratitude.

"It was incredible, quite surreal, [there's] disbelief but also tinged with sadness that it has actually come to an end," she told BBC Radio 4's Woman's Hour.

"It was this incredible time, some of it indescribable and then turning the book over and finding that we'd won, I don't think either of us had any words, we just kind of screamed and blubbed at each other for the next 10 minutes."

Since returning home they have walked the Inca Trail to Machu Picchu along with Cathie's husband, and are hoping to trek the Great Wall of China together in October.

Asked what she would say to someone considering going on a big adventure with their best friend, Cathie said: "Definitely - do it."

The third series of Race Across the World is available on BBC iPlayer.