The 1974 Ohio State Trooper is causing quite a stir in Centenary Square. Two sharp-suited guys in shades are leaning out of the vintage American police car chatting to a growing crowd gathering around the vehicle.

In the back sits a mannequin dressed as a nun, while out of the car stereo blasts Everybody Needs Somebody.

The two guys in shades introduce themselves as Jake and Elwood Blues. Since they're here promoting their show, The Best Blues Brothers Show in the World - Ever! coming to Bradford later this month, I assume they're in character. But it turns out their names really are Jake and Elwood Blues.

"We changed them by deed poll, " says Elwood. "My twin daughters are Harriet Blues and Georgia Blues - the first Blues Sisters."

To say these men are devoted to the Blues Brothers is like saying John Belushi was partial to the occasional glass of shandy.

Both huge fans of the 1980 cult classic movie The Blues Brothers, they spend practically all their time touring their show around the UK and countries from Norway to Morocco. They show me their driving licences, complete with passport photographs of them in suits and shades.

The show was launched by Jake in 1988 and Elwood joined seven years ago. While the film followed the attempts of brothers Jake and Elwood to reform their old blues band and raise $5,000 to save their old school, the show recreates the buzz of the original Blues Brothers live shows, with numbers like Gimme Some Lovin', Respect and Shake A Tail-Feather.

"John Belushi and Dan Ayroyd were gigging long before the film came along, " says Elwood. "Belushi wanted to be a rock star and when he was on Saturday Night Live he teamed up with Aykroyd to sing the blues then did some live shows. They recorded five live albums.

"The film was initially a flop but became a cult hit when it was released on video. It's a popular today as ever; we get people coming along aged eight to 80, the music is timeless."

Jake and Elwood have studied footage of the live shows to get the moves just right, but their obsession doesn't end there. They bought their '74 Ohio State Trooper on eBay!

"It cost £1,500, but a lot more to restore, " says Elwood. "We also bought a tour bus on eBay that has been used by the Rolling Stones and David Bowie.

"We're unveiling a new set on this tour, we've got five police cars lined up with a pick-up truck. It's a very fast show but it's great fun, we love it, " he adds.

"We've started taking the original blues songs and merging them with a Chicago jazz sound. As well as being a tribute to the Blues Brothers the show pays homage to the Chicago blues, soul and gospel that we grew up listening to.

"There are loads of Blues Brothers tribute bands but in my view it has to be just right. I learned to play the harmonica because that's what Elwood played."

The guys have performed with the likes of Ronan Keating and The Corrs and the original Blues Brothers band. "That was awesome, " says Elwood, who discovered the Blues Brothers as a child.

"I was off sick from school one day and stayed home watching the video, I loved it, " he says. "When I was 15 I joined a Blues Brothers tribute band and ran off to perform in Germany, despite my mum telling me that I couldn't go."

Elwood, from Liverpool, and Derbyshire-born 'Joliet' Jake Blues - who started drumming with beat groups 30 years ago and has worked with stars like Paul McCartney - are planning a nationwide fundraising stunt for the BBC Children in Need appeal later this year.

"In keeping with the spirit of the film, we want to raise money for charity so we're planning to tour from Scotland to the south coast, playing one song in every city we go through, " says Jake. "We're calling it the Blues Brothers Dash for Cash."

If determination and eccentricity is what it takes, I reckon these two might just pull it off.

The Best Blues Brothers Show In the World - Ever! is at St George's Hall on Thursday, March 30. For tickets call 01274 432000.