Memory expert David Thomas, pictured, is aiming to be leader of the pack.

For the 33-year-old is planning to memorise and recite 100 packs of playing cards - almost double the existing world record.

David, of Shelf, last entered the record books by reciting the mathematical formula of Pi - to 22,500 digits.

But memorising 100 packs of cards was the equivalent of being the first person to break the four-minute mile in the memory world, he said.

"The first person to do 100 packs gets their name on a tablet of stone," he said. "I didn't want to do the Pi again as I'd already done it. I just wanted to do something different."

A Guinness Book of World Records spokesman said the existing world record holder was Dave Farrow, of Ontario, who memorised 2,704 cards - the equivalent of 52 packs - on June 24, 1996, making only six mistakes.

David's attempt on February 18 will start at 6am and is predicted to last 21 hours. The 5,200 cards will be shuffled in a giant bag before being handed to him in bundles of 52.

He will be allowed to look at each card only once before reciting them in sequence and invigilators will only allow a maximum of 26 mistakes.

David said his secret was imagining a famous person while looking at the card.

"The two of clubs to me is Bill Clinton," he said. "You use B as two as it's the second number in the alphabet and C as it's clubs.

"It could be Barbara Cartland or Billy Connolly, but every time I see the two of clubs, I see Bill Clinton. The seven of clubs is Geoff Capes.

"It's a bit like looking at the letter A - it's not two lines with a bar across, you look at it as an A."

The former firefighter was inspired to pursue his talent after watching a TV game show starring five-times world memory champion Dominic O'Brien.

Self-taught, he now runs his own company advising businesses and speaking at conferences.

He will attempt to capture the record at the Holdsworth Hotel in Holmfield, Halifax, under the keen eye of a video camera, a former memory world champion and independent judges so he can verify his claim if successful.

He will also be supported by fianc Julie Holdsworth, who spent hours checking reams of figures as he practised for his record breaking recital of Pi.