Paralympic gold medallist Dan Bentley is trying not to laugh. I have joined the GB boccia player in training at his gym in Great Dunmow, Essex, and have just rolled my third blue ball miles wide of the jack. He knows he is about to clean up, and with three swift shots he knocks my paltry efforts off the court and creates a circle of red balls around the jack, leaving me with nothing.
Anyone channel-hopping through the Paralympic coverage this morning may stumble across a sport which at first glance looks not very sporty at all. At 9am, a line of three Britons and three Argentinians will be sitting stationary in electric wheelchairs occasionally rolling red and blue leather balls along the floor of the ExCel centre.
Don't let appearances deceive you. This is boccia (pronounced to rhyme with "gotcha"), a game as strategic as chess and as tricky as snooker. It is an adapted version of boules or pétanque, played by those with disabilities that affect their motor skills, such as cerebral palsy or muscular dystrophy.
When I first got an email from Bentley challenging me to a game, I was a bit wary. If it involved getting into a wheelchair, wouldn't that be about as politically correct as, say, putting boot polish on my face for the day? And, just as mortifying a thought, what if I beat him because the game was intended for those whose muscle functions were impaired?
I shouldn't have worried my patronising head. Bentley's hand may wobble slightly before he throws, but the 28-year-old's aim has a deadly precision. I don't use a wheelchair, but I try standing, sitting and kneeling – and over four games he doesn't let me get a single point on the scoreboard.
I throw the first jack, sending it straight out into the middle of the court, a bad tactic as it turns out. "I like to throw it off to the side nearest me," says Bentley. "It makes it harder for the opponent." This becomes all too apparent in the second round, when it is his turn to throw the jack and I struggle to get a single ball within yards of it.
Each time the jack is thrown, the players must get their balls as close to it as possible. At the end of each round the referee measures how far the balls are from the jack, and awards points for those closest. Unfortunately, since none of mine are anywhere near it by the time Dan has cleaned up, I get a definite zero.
In the second game, he soon sends my balls into orbit on the neighbouring court using a "bombing" technique of smashing my ball from above. By the third game he is openly guffawing as I try in vain to listen to his advice. "Roll it hard at that gap there," he says, pointing to a minuscule sliver between his ball and the jack that appears to be several miles away. I take aim and my ball careers at full speed several feet wide of the space he had indicated.
After four rounds, the final score is 12-0. "It's a very tactical game," he says, as he explains the snooker-like cannon technique that sent my only half-decent shot pinging away from the jack.
Today Bentley will compete as part of the British team who are the reigning Paralympic champions. This will include the captain and singles gold medallist Nigel Murray, who also has cerebral palsy and is in the same BC2 classification. At any time at least one of the three players in a team must be a BC1 athlete, so impaired they play with an assistant, who lines up a ramp for the ball to be thrown down.
Bentley will also play in the BC2 singles competition, though he faces stiff competition from Murray. Tucked underneath his wheelchair is a wooden case with his Beijing gold medal nestling inside. He is desperate to have at least one from London to join it. "I can say I've already got a medal but to get one in London would beat that."
Boccia is not a sport that ordinarily attracts crowds, and he is both nervous and excited about the prospect of today's audience. "Boccia is normally played in front of mums and dads and that's it. We never get a crowd, so I think we're going to enjoy it."