Many companies bill themselves as a 'family business', but few are executing this quite as effectively as Marshall Trailers, based at Bucksburn, near Aberdeen.

With no fewer than three generations of Marshalls actively working in the business, things truly are a family affair.

Founded in 1952, Charles J Marshall started his business in a back garden in the middle of Aberdeen. At 18 and a joiner by trade, with a starting investment of £5, he had to knock the garden wall down to remove his creation and sell it at the local mart.

Things have blossomed since, though, and his son and now his grandsons are carrying on his traditions and implementing his initial business plan of producing something that can be sold en masse.

Gone is the urban garden in Aberdeen and the company now sprawls over an impressive site on the outskirts of the city. Purchased in the early 1950s and originally a modest croft, Chapel Works has been built upon and expanded to the point it now comfortably produces between 2000 and 2500 Marshall products every year, to be sent to dealers and customers the length and breadth of the country and further afield.

In 1982, Charles Richard began his apprenticeship in the company, and, in 1988, became managing director. His sons, Charles Peter (23) and David (20), joined him 18 months ago and, like their father, have worked their way through many of the roles in the business, ensuring that that they have a thorough understanding of the set up.

"My grandfather is a great believer that nothing really beats the experience gained from doing it yourself," Charles Peter explains, "and that's a mentality that our father has instilled in my brother David and I, so we've both carried out various roles in the last 18 months.

"It's giving us invaluable experience, but there's no denying we both still have lots to learn, both from our father and grandfather, and from others in the business!

"My father started on the shop floor when he was just 15, so he really knows the engineering side of things inside out, it's priceless to have that sort of knowledge. Having business skills means very little if you can't understand your product!"

Both boys have degrees behind them, with Charles Peter having studied Law at Aberdeen, and David, Land Based Technology at Wiltshire College.

There are 50 full time staff in the workshop and five in the office. The company has taken on a new foreman, Clive Woods, who started last November, and he will fully take over when current, longstanding foreman, Ian Ross, retires in August.

The three younger Marshalls are all in the office and workshop full-time, and Charles J himself is also still in the office daily.

The company has dealers countrywide and have recently struck up new relationships, namely with Ernest Doe and Sons, in South-east England, and Platts Harris. They also have dealers all over, although have not had an official salesperson for 15 years, preferring to keep the sales element family based.

One of the main things the Marshalls are keen to embrace is what they see as the need to invest in technological advancements.

They have not long installed robot welders and they employ three squads of welders to make sure each area of the production line is well covered.

"Manufacturing is changing and you have to move with it or get left behind," says Charles Peter, as he shows us around the factory floor. "Marshalls is looked at as an older, more established, brand and we're really trying to update, develop and move into the future, for both our own benefit and to that of our customers, existing and new.

"The industry is one that is increasingly difficult to get a start in, so you really do have to meet customer needs and maintain that bond so as to hopefully ensure return custom."

Product-wise, Marshalls makes a widening range of trailers and machinery. Silage trailers are continually their best sellers year on year but the past decade has seen a growth in sales of their highly developed grain trailer line.

The 16-tonne trailer is the largest they produce, with that and the 14-tonne options selling more than ever before. All of their silage and grain trailers are made to order as they take on board each customer's individual specifications.

Products like their drop-side trailers and bale trailers are built in higher volumes and kept as stock, as they are less specific to each sale.

They have plans to develop further into dumper trailers and are keen to expand generally but, as Charles Peter explains, "you have to have a good base before you can build on it, both trailers wise and business wise, so there's no point in rushing these things. We pride ourselves on quality and good workmanship".

However, the company now produces, on average, 46 mixed units every week and these are sold throughout the world. Having celebrated 60 years in business in 2012, the team now also proudly boast that it is the UK's oldest and largest trailer manufacturer.

With this sort of foundation behind them and new blood in the company, it would certainly seem like the legacy of Marshall Trailers is set to continue for generations to come.