Careering down the crisp slopes of Ben Lawers in woolly sweaters and bobble hats, Scotland’s pioneering skiers took their first wobbly snowplough towards what was often an epic face-plant.

When the summer sun shone, a different kind of skier glided across the surface of Loch Earn, sometimes with impressive results, often not.

On beaches, up hills, in outdoor swimming pools, at family weddings, royal visits and while familiar places and features of Scottish life were dismantled or built in the name of progress, amateur film-maker Harry Birrell was there to capture it.

The result was hundreds of reels of film spanning seven decades which show life in a rapidly changing nation in all its familiar - and extraordinary - glory.

Left in Harry’s shed after he died, his treasure trove of film, photographs and diaries were recently dusted down and revisited in an intense labour of love by his grand-daughter, Carina.

Some of the gritty footage from his Second World War service in India as an officer with the Gurkhas was edited into a moving documentary, Films of Love and War.

Now a collection of scenes from Harry’s first efforts at film making, his early military career in East Lothian, carefree days spent exploring Scotland’s great outdoors and delightful family moments that will resonate with every Scot of a certain age, have been digitised to form a new BBC two-part documentary.

The films reflect simpler days from 1928 onwards, when Harry was handed his first cine-camera at the age of just ten and fell in love with what he later called “the greatest toy a child could ever receive”.

For decades to come he pressed ‘record’ on life as it unfolded around him, putting down on film a far simpler age when holidays were spent pottering on the beach in Arran, outdoor swimming pools attracted crowds to diving competitions and Scotland’s mountain slopes and lochs were under siege from adventurous young men and women seeking fun.

As well as intimate family gatherings and loving scenes of his three children from babyhood to teenagers, the films include epic shots of Scotland’s landscape, along with lost footage of the construction of the Forth Bridge which he used to make his own mini documentary of its construction.

Carina, 35, who produced the two new BBC Scotland documentaries which will be screened over the next two Tuesdays, says his footage captured moments of 20th century life that many viewers will find familiar – including charming family scenes of Harry’s children at play, wedding dances and summer holidays.

“When making the film, I knew it was going to be much closer to our family and I wondered how it would resonate with other people,” she says.

“But it evokes nostalgia and there’s a sense that it’s for everyone. It’s very emotional.”

She adds: “One of my grandfather’s biggest passions was to track how life and industry and landscape was changing around him. As things evolved, he loved to document how life was changing.

“He filmed what was accessible for him to film, but also things that he thought would be of interest to people in the future.

“He had a specific eye for appreciating what might be of interest in people.”

In his teens, he captured holidays on Arran pottering on the rocks and swimming in the sea off Blackwaterfoot on the island’s west coast, and conquering its highest peak, Goat Fell.

While he had the skills to pursue a film career, he opted to study as a surveyor before volunteering for army service in 1939, recording himself as he took the oath of allegiance.

At his officer cadet training unit in Dunbar in East Lothian, he filmed military training activities – some of which revealed the limits under which the over-stretched army operated - and morale-boosting recreation, when soldiers unwound by sunbathing, skinny dipping in the sea, sailing and enjoying the town’s huge outdoor pool.

He took his film camera with him during his seven years as an officer with the Gurkhas, and documented the unit’s training, the fall of Rangoon to the Japanese and his experiences of the battle of Imphal.

Those scenes were stitched together by award-winning filmmaker Matt Pinder to make ‘Harry Birrell Presents Films of Love and War’. Narrated by Bodyguard star Richard Madden, the documentary, which credited Harry as ‘director of photography’, was premiered at Glasgow Film Festival before being shown on television.

The same team is behind the latest two short films, which follow Harry’s film-making journey from teenager to his return from war to film the inaugural Edinburgh Festival – complete with dog agility performances – through fatherhood and into his later years.

Some of the most entertaining scenes are from the early 1950s, when Harry joined members of the new Dundee Ski Club as they explored the slopes of Ben Lawers and Cairn Gorm, attempting – and often failing – to find their ski legs.

For some, there is the gruelling effort of climbing uphill, skis crossed over their backs, while the luckier ones ‘enjoy’ a bone-jangling lift from an old army all-terrain vehicle – all long before the days of chairlifts, tows or the funicular railway.

In a flashback reminder to today’s paddleboarders, kayakers and open water swimmers that Scotland’s waters have always provided a playground for those with no fear of the cold, are scenes of water skiers on Loch Earn showing elegant experts and the less accomplished beginners.

According to Carina, his films showed the reality of Scotland at play – including the failures.

“His films were not about showing how amazing or wonderful something was,” says Carina. “He filmed people having fun, on an adventure or doing something challenging.

“Most people remember what it was like to fall on their butt when they were learning to ski, and it more charming and fun to see them that way.

“He was great at getting involved,” she adds. “And he loved the camaraderie of the outdoor community.”

Although film-making remained a hobby, he took a highly professional approach to his work, even constructing a home-made cinema in his Giffnock home with plush seats and ‘Hollywood’ gilding.

Sadly, he was diagnosed with glaucoma in the 1970s, which eventually robbed him of his sight.

Around 400 cans of film were found in his shed, sending the family on an emotional mystery tour into what they might reveal.

Around two thirds have been digitised, leaving scope for more nostalgic films to come. The collection has been presented to the National Library of Scotland for safekeeping.

“There’s definitely a lot more there,” adds Carina. “A big motivation for making these films was to celebrate his work and ensure it would be available to people.

“I think he’d be delighted to know that people today are able to see them.”

Harry Birrell presents Films of Scotland is on BBC Scotland on Tuesday, July 27 and Tuesday, August 3 at 10pm.