When a red eyed Sam locks eyes with Usain Bolt across an empty luggage carrousel he does what every man in his position would do.

He challenges the fastest man in the world to a race.

What ensues is a race through the sights of London as both Sam and Usain use their Visa cards to replace their lost luggage.From pedalos in Hyde park, tourist maps in Trafalgar square and a dash across the millennium bridge.

We take it all in before reaching our climatic finale at the start of the 100 metre final in Stratford.

Here we reveal Sam, smartly dressed, starter gun in hand, ready to begin the greatest race at the Olympics.

But he's just won his own, having just pipped Bolt to the stadium.