Race Across The World: As the teams edge closer to the finish line in Lombok and the £20,000 prize, they will all be tested physically, mentally and emotionally

Mother-and-daughter duos Brydie and Sharon, and Eugenie and Isabel; best friends Alfie and Owen; retired married couple Stephen and Viv, and brother and sister Betty and James all clearly thought it was when they set off from from Hokkaido, in the north of Japan, five weeks ago.

Since then, we have seen the pairs struggle without the trappings of modern life, passing through a series of checkpoints using both public transport and ingenuity, taking odd jobs to earn extra funds, and relying on the kindness of strangers.

Barely in touch as adults, sales consultant James took a bit of persuasion from his older sister, gym social media and events manager Betty, before agreeing to embark on the experience of a lifetime.

“It’s a TV programme that we watch as a family,” Betty explains. “During series one and two, we were sat there like ‘we could definitely do this.’

“I’ve never really spoken about it with my friends, so I think it was the more natural decision to go for James.”

Her brother adds: “It never really crossed my mind to actually go for it. I guess Betty’s got that ‘Why not? Let’s try it’ mentality whereas I maybe wouldn’t have actually applied by myself.”

Despite James’s initial doubts over applying for the show, the pair are now front runners for the first time.

However, the siblings find it hard to tear themselves away from the paradise islands of Koh Phi Phi, and indulge themselves with an expensive island-hopping journey across Malaysia to the Indonesian island of Sumatra and the sixth checkpoint in the mountain-fringed city of Bukittinggi.

The siblings also face a huge setback tonight when they arrive which threatens to bring their race to a premature end.

Determined to find a strategy that will put them ahead, Viv takes control of the purse strings and decision making from Stephen.

A stop-over on Thailand’s southernmost island Koh Lipe gives her the opportunity to reflect on the rebelliousness of her lost youth while she recoups some budget working in a beach bar.

Viv also convinces a reluctant Stephen to make a stop in the historic city of George Town in search of the 17th prettiest street in the world.

Alfie’s competitive spirit has been re-ignited after he and best friend Owen recovered from being 12 hours behind the leaders in the last leg.

While Owen is keen to visit the iconic Petronas Towers in Kuala Lumpur, Alfie is solely focused on speed and race position.

But a strategic leap across the maritime border to Langkawi marks a turning point for Alfie and he begins to warm to the Malaysian culture.

Two hours behind their rivals and in last place for the first time, mother and daughter Eugenie and Isabel take a chance on a different route to Malaysia.

Their risky strategy is to prioritise boosting their budget with farming homestays – despite an aversion to manual labour and creepy crawlies.

As the teams edge closer to the finish line in Lombok and the £20,000 prize, they will all be tested physically, mentally and emotionally.

They may not have their smartphones or bank cards, but the memories they have built up are sure to last forever.