The boss of the biscuits factory where McVitie’s chocolate digestives have been made for the last 100 years reckons people have always eaten them incorrectly.

Anthony Coulson, general manager at the company’s chocolate refinery and bakery in Stockport, said the teatime staple was originally meant to be eaten with the chocolate-covered side facing down.

“It’s the world’s most incredible debate, whether you have the chocolate on the top or the chocolate on the bottom,” mused Mr Coulson, who admitted he was a chocolate-on-top man.

The factory opened in 1917, with the chocolate digestive launched eight years later.

About 80 million packets are made every year, with all of the chocolate made in Greater Manchester.

Mr Coulson told BBC Radio Manchester: “One of the very first things I learnt when I got to join McVitie’s was chocolate side down to eat the digestive.

“Now up until then I’d always eaten it the other way round…You can do it exactly how you want to do it.”

Mr Coulson said the theory was “it starts to melt, you start to get the flavour and away you go”, adding: “It makes sense, right?”

The chocolate digestive was launched about a quarter of a century after the plain variety, whose name was inspired by the belief that the baking powder in the recipe would help with digestion.

Its creation came two years before one of the food manufacturer’s famous creations, the Jaffa Cake, which itself has become something of a confectionery conundrum.

And although people might think of the chocolate digestive as being topped with chocolate, the company has said that as the plain biscuits pass through a “chocolate reservoir”, the chocolate actually coats the underside of it.

Lynn Loftus, who has worked at the factory for 36 years, called the biscuit “timeless”, adding that she thought it would be around for many years to come.

Craig Leech, who has worked at McVitie’s for 21 years, started off in the factory by putting the chocolate on top of the biscuits.

“I just come in with a positive attitude. I know the people and the products inside out,” said Mr Leech, who is now a planning manager for the refinery.

Alix Knagg, who has been working there for six months, said the chocolate digestive was “still a great product 100 years on”.