A BBC documentary has revealed the story of how a daring brother and sister from Hitchin carried out a 700-mile journey to visit their grandmother off the coast of Scotland 70 years ago.

The Comet: Millie Bukojemsky reflects on her their journey in 'Two Go to Tolsta'. Picture: BBC AlbaMillie Bukojemsky reflects on her their journey in 'Two Go to Tolsta'. Picture: BBC Alba (Image: Archant)

It's the afternoon of Friday, August 12, in 1949. During their summer holiday, 13-year-old Millie Richardson and younger brother Syd, nine, are planning a visit to their grandmother.

Instead of a warm, Hitchin summer, the pair want to visit granny's "paradise" on the Isle of Lewis in the Outer Hebrides, more than 700 miles away.

Undaunted by a lack of money, clothes or provisions, the siblings leave behind a hastily scribbled note - "Going away camping for a few days" before embarking on an epic adventure.

With nothing but swimming costumes and stale buns in their backpacks, Millie and Syd's story reads like a classic children's adventure.

The Comet: Sydney Richardson reflects on his remarkable journey. Picture: BBC AlbaSydney Richardson reflects on his remarkable journey. Picture: BBC Alba (Image: Archant)

Two days later and after an arduous trip by train, bus and boat, they arrived at their grandmother's house in North Tolsta hungry and tired - but unscathed.

Millie, now in her 80s and living in Australia, looks back fondly on the summer of 1949, where she got the chance to star in her own adventure storybook.

She said: "I wanted to live there forever. It was so exciting for us.

"Milking the cows and fetching water from the well. My grandfather reading the Bible by the light of the tilly lamp. And swimming in that ice cold water! It was wild, and free, and magical."

The Comet: The pair risked a lot to visit their grandmother in North Tolsta. Picture: BBC AlbaThe pair risked a lot to visit their grandmother in North Tolsta. Picture: BBC Alba (Image: Archant)

Her brother Syd, a former journalist, remembers the pair being "mini-celebrities" in North Tolsta for having pulled off such a jaw-dropping trip.

He added: "We'd been there before and my big sister Millie was determined we'd go back.

"She led me astray - and I went happily!"

When it was revealed that the two had safely arrived at their grandmother's house 30 hours after leaving Hitchin, their anxious parents were understandably relieved.

The Comet: Millie Bukojemsky reflects on her their journey in 'Two Go to Tolsta'. Picture: BBC AlbaMillie Bukojemsky reflects on her their journey in 'Two Go to Tolsta'. Picture: BBC Alba (Image: Archant)

And by Monday morning, newspapers across the country were sharing Millie and Syd's remarkable runaway story.

The programme, produced by Sorbier Productions, marks 70 years since the siblings set off and features reflective interviews with Millie and Syd, who returns to his grandparents' home.

'Two go to Tolsta' is a 30-minute documentary that will show on BBC iPlayer until the end of the month. You can watch it here.