IT began with a trip to a rubbish dump in India, where locals would pick through the trash for anything they could use again or sell on.
While working for a charity which helped these scavenger families, Toby McCartney noticed that as well as making money from the rubbish, the 'pickers' also had an unusual use for plastic.
Taking bags and broken crates and boxes, they would fill the potholes which bedevilled nearby roads and burn the plastic until it melted and filled the rutted surface, creating a durable filler.
Now that idea has spawned a business which Mr McCartney, now CEO of start-up company MacRebur, believes could save the world from the scourge of plastic pollution.
Toby McCartney and friends Gordon Reid and Nick Burnett
Every year 270m tonnes of plastic are produced worldwide, a number which is set to double in the coming decades.
But each year almost half will end up discarded and in landfill - with around 10-20 million tonnes washed into the sea from every coastline in the world.
READ MORE: First look at Scots factory hailed most important in world for turning plastic into roads
Estimates vary, but some studies have suggested that around 300 trillion individual items of plastic - including microbeads and broken down 'mermaid tears' from bigger items - have accumulated in the world's oceans wince plastic was first used just a century ago.
This has led to the deaths of vast swathes of sealife and seabirds, either tangled in plastic strips or from ingesting microscopic amounts until they become toxic.
It was the plight of these creatures which got Mr McCartney thinking about ways to tackle to problem of waste, after something his daughter said at school
During a recent TED talk, he said: "The teacher had asked the kids 'what lives in our oceans?'. And after a few answers my little girl put her hand up and she said said 'plastic'.
"Now I don't want my little girl growing up in a world where this is the case.
"So we must revalue and we must reuse and reduce the plastic epidemic that we all live through today."
Turning his mind to his time in India, the engineer realised he had a potential solution, one which could put the plastic to use without it having to be incinerated or buried in the ground.
It took 18 long months, and hundreds of trials to find the right mix and a way to bond plastic to the road surface without it breaking down and leaching out into the surrounding land.
READ MORE: Dumfriesshire firm has made a quick impact on the road building sector
But despite the enormity of the task, Mr McCartney says he and his team have cracked the problem and come up with a way to turn plastic bags into hard-wearing roads which last more than 60 per cent longer than normal.
He said: "We couldn't believe it. The results are that not only can we use up the waste plastic in our roads to make out roads better.
"But our roads are up to 60 per cent stronger than the roads you currently drive on because of the waste plastics we put in, and they are up to ten times longer lasting. And they don't [form] potholes."
Now the company is taking its next step, by opening its first factory in Lockerbie. A factory which could become one of the most important in the world.
Mr McCartney said: “The opening of our first ever factory is an important milestone in our mission to tackle two issues – plastic waste and potholed roads.
“Our technology means that we can not only help solve the problem of plastic waste but also produce roads that cope better with changes in the weather, reducing cracks and potholes.
READ MORE: Firms win prestigious business awards
“That’s because our roads are more flexible thanks to the properties of the plastic used in them, so although a MacRebur road looks the same as any other, it has improved strength and durability.
“Our technology also means there are no plastic microbeads present in the mix and we can even recycle the road at the end of its lifespan, creating a circular economy that is sustainable and cost effective.”
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules here