Oh Fabio, what have you done. Capello’s decision to leave Theo out of the World Cup squad was a mistake – how big a boo-boo we are about to find out. But next time England finds itself unable to break down a team’s defence or struggling to mount a counter-attack, ask yourself this:  ‘where’s Wally?’ Sadly, he’ll be chilling on the sofa with Melanie rather than warming up on the touchline waiting to explode into action.

Proof of the importance of Walcott to England’s chances of silverware struck me last night when one of Algeria’s World Cup coaching team approached me with a look of relief on his face. “Walcott’s not in England squad,” he said before mopping a bead of metaphorical sweat off his brow. This must have been the reaction of so many of our rivals. Can you imagine them expressing the same opinion had Shaun Wright Philips been left out of the squad?

The fact is that Walcott is one of the players our rivals dread. Pace as we all know is what defenders fear most and there are few players on the global stage who boast more of it than Walcott. He’s certainly the fastest player in the Premier League and according to data captured by Castrol, he hits top speeds of 22.72 mph. Incredibly, that’s not far shy of Usain Bolt.

“He’s faster than our whole team put together.” That was Barcelona coach Pep Guardiola’s comment after Walcott had shredded his defence in a second half cameo in the quarter-final of the Champions League that dragged the Gunners back from 2-0 to salvage a draw.

OK, so Theo’s final ball is not always reliable but when he hares down the touchline he stretches defences and makes space for other players to operate. He’s capable of moments of breath-taking football. There was for example, his coolly-taken debut strike for Arsenal against Chelsea in the 2007 League Cup Final and the pitch length dash against Liverpool to set up Emmanuel Adebayor in the semi-finals of the 2007/08 Champions League.  He can finish too. Just watch the way he side-footed the ball under Barca’s keeper for Arsenal or scored that hat-trick against Croatia in 2008 that helped England on the way to South Africa.

Admittedly, the player’s lack of consistency and progress is frustrating. But there are mitigating circumstances. Walcott has suffered with injuries. Last season was ravaged by a series of back, knee, hamstring and rib problems. While in 2007 and 2008, he had to undergo operations to repair a hereditary weakness in his shoulders. There is no disguising that these ailments have held back his development as a player.

Right now the Arsenal man may be short of form, confidence and yes, maybe even footballing intelligence but his lightning feet still fill defenders with fear. They should have been England’s deadly – if not so secret – weapon for 2010. Yes, Walcott doesn’t deserve to make the starting XI – Aaron Lennon has earned that right – but he most certainly he should have gone to South Africa as an impact substitute. Before a ball has even been kicked in South Africa, Fabio Capello has scored a terrible own goal.