Peppa Pig: Comedian John Sparkes behind cartoon voices

He could be described as the most reliable babysitter you never knew you had.

John Sparkes is the understated Welsh comedian who does not just narrate the $1bn (£890m) Peppa Pig global franchise - the UK's greatest cartoon export - but he is also the lyrical wizard behind children TV's favourite characters.

As he walked into Paddington Station - fitting for cartoon royalty - the 63-year-old former bank clerk and English teacher did not raise a glance.

Yet, in the right crowd, if he burst into an impromptu "Peppa and George like jumping up and down in muddy puddles", we may have had company.

He is the vocal mastermind behind Peppa regulars Mr Rabbit, Mr Pony, Mr Potato, Mr Fox and Mr Mole.

Sparkes may also be recognised from Ben and Holly's Little Kingdom, as Fireman Sam and from Shaun the Sheep.

"I bumped into an old comedian mate a few years ago and his little boy was a huge Peppa Pig fan," Sparkes said.

"He made the mistake of saying 'this is the man that does the voice of characters in Peppa'. The little lad didn't like it because it ruptured his imaginary world, as for him Peppa Pig is real.

"So a message for grown-ups... if you're sitting at home now reading this story on the internet and show your kids this is the man who is Mr Rabbit, they won't thank you for it."

His TV career started on 1980s cult comedy Naked Video as anorak-wearing Welsh poet Siadwell - but his showbiz career really began alongside a Hollywood A-lister.

Catherine Zeta-Jones was in the same variety show at Swansea Grand Theatre and Sparkes, then a young wannabe comedian, was in the 1st Gowerton Scouts.

"My mates and I wrote a comedy sketch show that we performed at the Grand in the The Gang Show," said Sparkes, who grew up in West Cross, Swansea.

"It was a show for local Brownies, Scouts and Cubs groups. I remember Catherine Zeta-Jones, who I think was from the Port Talbot Brownies, was in a choir.

"That, ladies and gentleman, was where it all began! For both of us, I suppose."

After a pit stop as a clerk in Lloyds Bank's Mumbles branch, a computer studies degree at Oxford Polytechnic and a drama specialist at a Bicester comprehensive school, his professional comedy career started in a vegetarian restaurant.

"My first real booking was at the Earth Exchange in Archway after I took the gamble to chance it in London," he said, recalling joining Eddie Izzard, Alexi Sayle and Jo Brand on the alternative cabaret circuit.

"I thought vegetarians would be kind. It went ok, I surprised myself... I started making a living and paying rent on my flat."

His broadcasting breakthrough in 1984 came alongside Rab C Nesbitt stars Gregor Fisher and Elaine C Smith on Naked Video and on BBC Radio 4's Absolutely sketch show.

As Absolutely became a TV hit on Channel 4, Sparkes' popularity grew - especially with two animation graduates from Middlesex Polytechnic.

"Mark Baker and Neville Astley, the creators of Peppa Pig, used to watch Absolutely and they got in touch to ask if I'd like to write with them for an animated series called the Big Knights - I've worked on every project they've done since."

His first Peppa project was 218 episodes ago.

He has remained a Peppa Pig mainstay, with the show now screened in 180 countries, from the United States to China. It has an estimated 200,000 associated products from a theme park to nappies.

"It surprised me when they asked me to narrate," he said.

"Why did I do it? It was a challenge and sounded interesting - and I haven't got to write or learn the words so I would've been a fool to say no."

Born: 9 January 1954 in Swansea

Family: Wife Beverly and daughters Isobel, 24, and Emily, 18

Favourite comedians: Peter Sellers, Peter Cook, Dudley Moore, Monty Python, Not Only....But also

Favourite cartoon: Tom and Jerry

Notable works:

Its popularity since its Channel 5 TV debut in 2004 is off the scale.

Eight billion YouTube hits and two cinema releases later, a further 117 episodes have been commissioned, with owners Entertainment One hoping to conquer France, Canada and Latin America as it aims to make Peppa a $2bn (£1.8bn) brand by 2020.

"It's like a classic pantomime, it's got a bit of humour for the mums and dads while keeping the children entertained," he said.

"And often cartoons hire comedian voice artists for that comedic tone and delivery."

Sparkes insists he is just a "voice for hire".

But here is the man behind why Peppa favourite Mr Potato is French and why Mr Rabbit sounds like a Welsh civil servant.

Yet as the narrator, he knows he is not just an entertainer but an educator.

"You must remember this is for young children who are learning how to speak English. So you must speak clearly, ensure you enunciate correctly, pay attention and sound cheerful," he said.

For a man who spends half the working week in a voice booth "the size of a telephone box", it is perhaps no surprise walking and nature are his biggest loves.

"I love nature and trees. I paid the council to put up another 10 trees in our street to make it feel more rural," he said.

"And while walking, I'm at my most creative. Nature gives me that opportunity to clear my head and allows me to concentrate without distraction."

So what does his average week look like for John?

"It's about seven days, I'm a bit of a traditionalist like that."