A Harlesden factory is the subject of a BBC Two documentary to be aired on Tuesday (August 1) looking into one of Britain's favourite treats.
Europe's largest biscuit factory churns out 80 million biscuits every day, chief among which is the universally adored chocolate digestive.
Greg Wallace received a tour of the Pladis McVitie's factory in Waxlow Road from Laurence Kothari, who has worked at the factory for nearly 38 years to see how the biscuits are made.
Production starts with the arrival of 28 tonnes of flour, rolled and turned into the biscuit with a layer of chocolate applied to the bottom.
That's right we've all been eating the biscuit the wrong way up.
The factory, which opened in 1902, employs around 580 people and produces 2,500 tonnes of biscuits every single week.
The Harlesden factory makes 22 different varieties all in all, including Hobnobs, Rich Tea and savoury snacks like Mini Cheddars.
Chocolate digestives have been made at the site since 1925 with 13 million of the biscuit made every day.
Mr Kothari said: "I was only meant to be here for six months but it was such a special place to work that here I am 38 years later. I think that’s down to the great people who I work with.
"There is no such thing as an average day, because every day is different. I never know what I’m going to get, which is what makes the job challenging, exciting and fun.
"The most interesting part being able to bring people’s ideas to life. If someone has an idea for a improving our production, we’ll find an engineering solution and make it happen."
When asked about the debate over whether the humble digestive really needs chocolate adornment, Mr Kothari said: "There’s something special about a plain McVitie’s Digestive, but adding chocolate is never a bad idea."
McVitie's is owned by Pladis, an international company which is headquartered in Uxbridge.
Previously on the show, Greg Wallace and co-presenter Cherry Healey have previously delved into the factories that make cornflakes, baked beans and bread.
Inside The Factory airs on Tuesday (August 1) at 8pm on BBC Two and on iplayer.
Keep up to date with the latest news in west London via the free getwestlondon app.
You can set up your app to see all the latest news and events from your area, plus receive push notifications for breaking news.