Image copyright Thoip Image caption Shoe repair and key-cutting business Timpson likes to hire Mr Happys

If you had to pick a Mr Men character that you thought was most like yourself, which would you choose?

Mr Happy? Mr Grumpy? Mr Clever? Or perhaps Mr Impossible?

With global sales of more than 120 million, many of us remember the much-loved Roger Hargreaves books from our childhood.

But as enjoyable as the tales are to read, few of us would have thought that they had a practical application in the world of business.

Well that's the case at UK shoe repair and key-cutting business Timpson, which recruits new staff solely according to which Mr Men characters their personalities resemble.

You can turn up for your Timpson interview with the world's finest CV or resume, and all the interviewer will do is work out whether you are a Mr Lazy (you don't have a hope), or a Mr Cheerful (you have a very good chance).

"We purely interview for personality," says Mr Timpson, who has been leading his family's firm for the past 42 years.

Image copyright AJ Levy Image caption John Timpson came up with the Mr Men recruitment policy

"We're not bothered by qualifications or CVs. We just look at the candidate and work out who they are, are they Mr Grumpy, Mr Slow, Mr Happy?

"If they tick all the right boxes then we put them in the shop for half the day. That's it, I dreamt that up years ago."

In explaining the thinking behind this rather novel approach to recruitment, Mr Timpson, 74, says that while you can train someone to do a job, you cannot train their personality.

And if you look at the continuing performance of the business, the Mr Men method appears to work rather well.

Timpson, a household name in the UK and the Republic of Ireland, saw sales rise 8% to £130m in the year to September 2015, with pre-tax profits up 65% to £10.3m.

'Can't train service'

As you have no doubt already gathered, Mr Timpson doesn't like to run his company - which was set up by his great-grandfather in 1865 - according to business convention.

Another factor that he says has been integral to its success is what he calls an "upside-down management approach", which gives the 1,325 Timpson branches a vast amount of autonomy.

Image copyright Timpson Image caption The firm has 1,325 branches across the UK and Republic of Ireland

Mr Timpson, who has the chairman role, says: "You can't train for great service, it's not by issuing rules or notices in the back of the staffroom.

"You only get great people when you give them the freedom, so we let them [staff] charge what they want. Here you can't tell people [the workers] what to do.

"So very often if a customer doesn't have the money, they can say 'don't worry, give us the money next time'."

Timpson employees can also spend up to £500 to settle a customer complaint, without having to check first with head office or a senior manager.

But how does Mr Timpson ensure that workers are running a business and not a charity? He returns to the hiring process.

Image copyright Thoip Image caption Move along please Mr Grumpy

"When store managers pick people, they get good people," he says.

"And the staff get a weekly bonus depending on how the shop is doing. They're not giving the business away, we're trusting them to be commercial."

Another key policy at Timpson is to hire people who have a criminal record, with 10% of its 4,700 employees having served time in prison.

Image copyright Timpson Image caption The first Timpson shop opened in Oldham, now part of Greater Manchester, in 1865

Giving former criminals a second chance was the brainchild of Mr Timpson's son James, who since 2011 has been the firm's chief executive.

Mr Timpson senior says: "I was a little apprehensive at what other people would think, but I was proved wrong.

"Our colleagues take great pride it in, and our customers like it too."

Boardroom battle

John Timpson first joined the Manchester-based family firm as a teenager, working in a number of stores. At the time the company didn't just repair shoes, but also made and sold them.

After university he joined shoemaking rival Clarks on a graduate scheme, before moving back to the family firm, and working his way up to buying director by the age of 27.

Image copyright Timpson Image caption Mr Timpson had to regain control of the business in the 1970s

However, in 1973 Mr Timpson and his father were forced out of the business after a boardroom bust up that saw his uncle take control.

The business did not fare too well without them though, and in 1975 Mr Timpson returned as managing director, and it was the uncle's turn to depart.

Eight years later Mr Timpson led a £42m management buy-out from the firm's then parent group, returning it to family ownership.

It was during this time that he made the decision to sell the shoe shops "because they were heading nowhere", and instead focus on shoe repairs.

The firm has since gone on to diversify into key cutting, watch repairs and selling house signs. It has also bought photography businesses Max Spielmann and Snappy Snaps, and the dry cleaning division of Johnson Services.

Retail analyst Richard Hyman says other store chains could learn a lot from Timpson.

"Timpson couldn't be a more unglamorous or unexciting business to be in, yet they manage to be dynamic and innovative," says Mr Hyman. "They are a breath of fresh air.

Image copyright Claire Wood Image caption Son James Timpson now holds the chief executive role

"Timpson as a group is alive and kicking, and that's more than can be said for a lot more mainstream retailers."

While Mr Timpson has no plans to retire, it is his son James who now looks after the day-to-day running of the company.

This has enabled Mr Timpson senior to write a newspaper column and release a number of business books, including his latest entitled Keys To Success.

In addition to his career in business Mr Timpson has had a very busy family life. In addition to five kids of their own, he and his late wife Alex - who died last year aged 69 - fostered no less than 90 children throughout their marriage.

Mr Timpson says that fostering "taught me a lot about people".

Image copyright Timpson Image caption Timpson staff are given a lot of autonomy

"I still try to help children in schools, and educate teachers on why children in the care system often behave the way they do."

Often travelling around the UK to visit stores, Mr Timpson says "it's really nice going to a shop that's well run".

"It's bloody nice when a customer says how nice that guy was. It's also nice to have a company that has values based on kindness and generosity.

"You can do good and make money at the same time."

Follow The Boss series editor Will Smale on Twitter @WillSmale1