20:45 28 March 2016
Pencil manufacturers are unable to keep up with the growing popularity of adult colouring books as more and more grown ups seek to switch off their electronic devices to de-stress.
Faber Castell, the world’s largest pencil manufacturer, has already added extra shifts to cope with the demand.
Illustrator Johanna Basford is the woman credited for sparking the craze because of her beautifully drawn books. The 32-year-old said: "People like colouring-in because they are fed up with digital.
"There is something nice about picking up a pencil and a pen. You are not going to get interrupted by Twitter, and there is also a childhood nostalgia element to it.
"The last time you did a bit of colouring in, you probably weren't about thinking about mortgage or Brexit.
She added: "I used to do all my work in black and white, and some of my clients used to joke about how they would like to take them home and colour them in.
"I was then asked to do a children's colouring book, and I said 'how about doing an adults' one as well?'. They were a bit tentative, but eventually they went for it, and printed 13,000 copies that sold out within a few weeks.