"The pain was very, very, very significant.

The Hour Record is a permanent, total, intense effort, which can't be compared to anything else."

Eddy Merckx- Hour Record holder 1972-1984.

This evening, Bradley Wiggins will undertake one of the most rigorous tests in cycling, perhaps in all of sport. The 35-year-old will attempt to break the Hour Record. It is one of the most distinguished of all records and one which has been held by some of the most revered athletes in cycling's history; Fausto Coppi, Eddy Merckx and Miguel Indurain have all been Hour Record holders at one time or another.

In past decades, holding the record for pushing yourself as far as you can ¬- both and literally and figuratively - around a velodrome was considered as prestigious as any achievement within cycling but, since the turn of the century, interest in the feat waned to such an extent that few attempted it. Indifference melted away last year when a rule change regarding permitted bike technology, along with the UCI effectively resetting the record mark, to reignite riders enthusiasm for the Hour Record. Wiggins' attempt today has captured public attention with the 6000 available tickets for the Lee Valley VeloPark Velodrome in London selling out in a matter of minutes.

Wiggins may have four Olympic gold medals and be a Tour de France winner but make no mistake about it, the superhuman effort facing him as he embarks on his record attempt will be one of the toughest challenges he has ever undertaken. The current record stands at 52.937km, set by fellow Brit, Alex Dowsett, last month. Wiggins is not aiming to merely break Dowsett's record though, he is aiming to shatter it.

One man who knows exactly what Wiggins will go through today is Graeme Obree, the Scot who twice broke the Hour Record in 1993 and 1994. The 49-year-old, who was also twice individual pursuit world champion in the 90s, managed a best effort of 52.7km and describes holding the record as his greatest sporting achievement.

"The Hour Record is the ultimate test of a man and a bike," Obree says. "It's not actually the physical effort that's the hardest thing, it's the mental effort. When you get to the sharp end, something else has to drive you on because you just can't think anymore. You've got to want it so badly because it's so painful."

Obree describes the effort required to break the record in intriguing ways. He likens the strength required to that needed when one is stranded in the desert and must reach an oasis. Or the strength that must be found when fleeing a burning building. Even now, over 20 years on, the strain shows on Obree's face when he recalls just how much effort he put into his record attempt. It appears that he can still feel every pedal stroke and remember every lung-bursting breath that he took during those tortuous 60 minutes.

"It's very hard to describe the feeling in normal terms," he says. "You're riding to the edge of mental and physical destruction. It's like being at the dentist and getting your teeth drilled out but you've to do the drilling yourself. It's a bit like a dance ¬- there's a rhythm and even though it feels awful, you must keep going. It was my mental strength that allowed me to break that record rather than my physical strength- your body can actually be pushed harder than you think. When I finished the hour, I didn't really feel anything because by that point, I was emotionally dead because I was so exhausted."

The general consensus is that Wiggins will break the record today and Obree concurs entirely with this prediction. Obree believes the real, flat-out, record attempts will begin today; the attempts which require every fibre of one's body to not just want to break the Hour Record, but to need to break it.

"Wiggins will break the Hour Record," predicts Obree, confidently. "I really admire his tenacity and he's got the ability to do it but it remains to be seen if he's got the personality to really take it to the edge, although I believe he will. I think that he'll get 54.5 or 55km. Wiggins will only attempt this record once and he'll do it right. He'll want to put it to bed. He knows that this is the last chance in his career to do it and I believe that this will truly be the hour record. If I was Wiggins, I'd make sure that there was nothing left in the tank at the end because he has a chance to do an Eddy Merckx; Merckx held the record for 12 years and Wiggins can do that too - he can scare everyone off attempting it for 10 years to come."

Obree's prediction that Wiggins will not merely do enough to better Dowsett's mark but, in fact, set a target that is unlikely to be beaten for a considerable time seems perspicacious. Wiggins has described the Hour Record as cycling's Holy Grail and has said that breaking it would be the cherry on top of his already remarkable career. If Wiggins breaks the record today, it is likely that Dowsett will make another attempt, which sparks comparisons with Obree's rivalry with Englishman, Chris Boardman, in the 1990s, which so excited the cycling fraternity.

"I definitely think there are similarities between the Dowsett/Wiggins rivalry and the one I had with Boardman," says Obree. "Dowsett is me ¬- he's the underdog. He's not got the best equipment and technology whereas Wiggins has the whole British Cycling machine behind him. And Dowsett set his record in Manchester which is a good velodrome but it's not as good as London so it's not a level playing field. But I think that Dowsett only has one more go in him because emotionally, it's hard- professional bike riders do not want to attempt it and fail. If Wiggins breaks the record today, which I expect he will, Dowsett will have a go at that and he'll either break it again or he won't. And then that could be it for a decade."

Whatever happens today, Obree believes that the reinvigoration of the Hour Record is a glorious thing for cycling. And there is, he believes, something special about watching someone push themselves to the very edge, as the Hour Record requires them to do. "Attempting the Hour Record tests your whole physical and spiritual being," he says. "What I love about the Hour Record is that it sounds so horrid but it's also so beautiful. The thing is- it's a yes or a no; you either get it or you fail. It's like jumping over the Grand Canyon- you make it or you don't, there's nothing in between. If Wiggins really goes for it today, we'll see someone destroy themselves on a physical, emotional and spiritual level and people like to see athletes destroy themselves. Breaking the Hour Record is right on the edge of human ability."