Kristian Stefanov hits speeds of up to 70mph in his go-kart - and he’s only 11.

Stefanov, a pupil at Gravesend Grammar School, sits fifth in class with two meetings to go in the six-round Ultimate Karting Championship.

He got his first go-kart aged five, and started racing competitively when he was six.

Dad Martin, who set up family team STF Racing, says he struggled to keep up with Kristian, who has gone from strength to strength.

He hits big speeds in the Rotax Micro Max class - quite a buzz for the young flier.

“You hit 70mph at some tracks but, depending on the set-up, you can easily hit 80mph,” said Martin, who is also Kristian’s mechanic. “They are rapid little machines.

“It depends on the track. There are tracks where you need better acceleration but less top speed and others where you need better top speed but less acceleration.

“It’s a balance you have to find on the day.

“The adrenaline racing at those speeds is incredible. Where you’re pretty much sitting on the floor, it makes it feel even quicker.”

Running a team isn’t cheap - it costs more than £30,000 a year to keep STF Racing going.

The Stefanovs are grateful for the backing of sponsors, including Gravesend accountancy firm ATN Partnership, who recently came on board.

Funding helps keep the family team competitive against established rivals.

“We set up the team to be able to compete at national level,” said Martin.

“There’s big teams, really professional, but we’re still pretty competitive and we have a good fight with all these guys, which is really awesome.

“It’s very challenging but at the same time very enjoyable because we put a lot of hard work in and all of a sudden it pays off.

“On race weekends you’ve got to find the right set-up and that’s not easy as a private team because you can only take data from one kart, where other teams have three, four, five, or even more.

“I do the mechanics and I’m teaching Kristian bits and pieces that he can pick up as well. It’s important for the drivers to understand the technical part of it - very beneficial.”

Stefanov looks up to ex-Formula 1 world champion Nico Rosberg.

The dream is to emulate his idol and get a seat in F1 but in a sport dominated by money, enjoyment is the priority.

“We only started as a bit of enjoyment, really, just to put a smile on the face,” said Martin.

“Year after year, he started getting deeper and deeper into the sport and more into the detail of it.

“His ultimate dream is to drive a Formula 1 car but to get into Formula 1 needs a lot more than we’re able to give him.

“We’ll keep doing what we’re doing all the time the enjoyment is there and whatever comes, we’ll take it.

“As long as he’s enjoying it and we can keep going, that’s what we’ll do. Racing is there to enjoy.”