It was only six hours into a charity challenge to climb Two IFC in Central 23 times - at 8,850 metres the equivalent of Mount Everest - that the Hong Kong police force's fitness guru realised all the training in the world was not going to get him through. Mark Sharp - who claims the force is one of the world's fittest because of the city's unforgiving climate and varied terrain - was stricken with vertigo and his body wanted to shut down. But his partner, teacher Graeme Deuchars, stepped up to encourage him through the next 11 hours of the mind-numbing monotony of trudging up those stairs. Each ascent of the 88-storey, 420-metre tower is the same as walking from Central up to The Peak. The pair were thankful to be taking the lift back down. 'I've done 37 marathons, but nothing has been as tough as that,' Sharp said after finishing the challenge last night, as he struggled to down a glass of champagne. 'It's quite simply taken everything out of me, but there was a time there when I didn't think I would make it.' On the eighth ascent, the dizziness became too much, and Sharp was told to lie down by medical support staff. 'He has tremendous mental strength that allowed him to go on when his body just wanted to sleep,' Deuchars said. The agony didn't stop Sharp talking about the climb as an annual event. 'This is something I really think businesses would warm to as a way to raise money for charity because [Two] IFC is such an icon.' So was the Scottish teacher at the German Swiss International School still sprightly at the end of the 17 hours, 36 minutes and 57 seconds? 'You have bad days and good days, and this was my good day,' Deuchars said. 'I feel brilliant.' Money raised by the event - possibly a world record - will go to the Hong Kong Sports Association for the Mentally Handicapped, the Markus Knosel Project and Oxfam.