I am sure there was a reason why it seemed a good idea to come to this chaotic bachelor flat in Derby, but I can't quite remember what it was. Which, come to think of it, may be precisely the reason.

It took British memory champion, Ben Pridmore, a moment to remember where he had put the cloak he was given in Brazil Ben Pridmore, the man cheerfully picking his way between piles of clothes and DVDs, may have the knowledge I seek. He may hold the key to the question that, eventually, every man must ask himself: how do I stop walking into rooms (and flats) only to discover I have forgotten why I went there in the first place? As the newly crowned British memory champion, Mr Pridmore, 30, also carries the hopes of a nation on his slightly drooping shoulders. Soon, he must do mental combat in the World Memory Championships in Manama, Bahrain.

He may look like a bespectacled accountant. He may have the kind of knees that regularly kept him off games from the age of 12, but this man is all that stands between us and the Teutonic might of the Germans.

He has a lethally honed hippocampus (brain area associated with memory). He will claim the World Championship back for Britain , which invented the sport and dominated it until Clemens Meyer, a 20-year-old law student from Bavaria, seized the world crown in 2005, and retained it in 2006.

He will depose Herr Meyer and wrest the number one spot in the overall world rankings from Dr Gunther Karsten, 46, the memory grandmaster from Erfurt.

Just not now, at the end of a long day. It's not that Mr Pridmore can recite pi to only 64 decimal places today.

It's more that he, er, can't remember where he set his world memory record. "I remembered 27 packs of cards in an hour," he says. "Last year, at the World Championships. In London, somewhere in London. Erm, where was it? No. It's gone completely."

But he remembers that "I hold all four card-remembering world records, and both binary number records. I think they are the only memory records I hold at the moment, although I have quite possibly forgotten a few".

He starts rooting among the piles of clothes. "Brazilian TV gave me this wonderful cloak. They flew me to Rio, just to memorise a pack of cards. Now, where did I put it...?"

At which point The Sunday Telegraph ventures to inquire: "Er, Mr Pridmore, would you say you are a forgetful person?"

"Oh yes," he says happily. "I forget everything. Go into a room and wonder why I am there? Happens to me all the time... Ah! there it is." Mr Pridmore has found his Brazilian "man of mystery" cloak.

He competes at the World Memory Championships from August 31 to September 2. The championships, a 10-discipline "deca-mentathlon", were created by Tony Buzan, 65, who has published and lectured worldwide on his Mind Maps system (and is also, according to his press release, a published poet, an honorary black belt in Aikido and a man once called "the greatest thinker since Aristotle"). He staged the first competition somewhere in London (the Athenaeum club, Mr Pridmore) in 1991.

Mr Buzan, advising me from the non-chaotic grandeur of Home House, a private members' club in London, says: "There were questions to be answered: are we just born with good memory? Can memory be changed in terms of its power? What is its potential? Its limits?"

The answers exceeded scientists' wildest expectations. In the mid-Nineties, they predicted no human would memorise a spoken number of more than 30 digits. At last year's championship, Clemens Meyer remembered a 188-digit spoken number, and could still recite it five hours later. Backwards.

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