Alexander Wurz's lap of Barcelona.

West McLaren Mercedes 'third driver' Alexander Wurz describes a lap of the Circuit de Catalunya, Barcelona - site of this weekend's Spanish Grand Prix:

"Accelerating downhill along the start-finish straight you hit 190mph/310kph in seventh gear before braking hard for the right-hander of Elf corner, which acts as a funnel at the start of the race and is often the site of first lap incidents. You can hit up to 4.8G under braking as your speed reduces to 86mph/138kph in second gear."

"The second corner, the uphill left flick of Elf at 118mph/189kph is in third and flat out in qualifying. This is immediately followed by the long demanding sweep of Renault, powering through the 180-degree right hander you reach 170mph/273kph on the exit. You continue to push hard on the throttle for the short straight that leads to Repsol, reaching some 180mph/ 290kph in sixth gear before braking hard for the tricky right hander."

"You enter Repsol in second gear at 85mph/137kph, increasing your speed as you are swung round the right curve, exiting at 155mph/252kph. A short burst of acceleration takes you down to the Seat hairpin."

"Hard on the brakes the track drops as you negotiate the tight left-hander at 60mph/97kph in second gear. Accelerating out of Seat, the track sweeps through a gentle left curve reaching 160mph/272kph in fifth gear before once again braking hard for the difficult left of W?rth, which is taken in second at 85mph/136kph."

"W?rth leads you onto a short uphill straight. A spurt of gas sees your speed hit 147mph/236kph in fourth gear on the approach to the blind right-hander of Campsa. Negotiated at 135mph/217kph in fourth gear this is a tricky corner with a large bump as you turn in. Campsa leads onto the fast Nissan straight, which sees you reach speeds of 180mph/290kph in sixth gear before braking sharply for the La Caixa hairpin. The left turn is taken in second gear at 65mph/104kph as you climb on the approach to the double right apex of Banc Sabadell."

"Entering the bumpy corner at 80mph/128kph in second, you push hard as you exit the second apex, building up speed on the short straight that leads to New Holland. The right hander is taken flat out in qualifying, and in the race you lift slightly to negotiate it at 150mph/241kph in fourth gear."

"Another short straight follows that leads you to the final corner, a very fast right hand turn that is taken at a minimum of 140mph/225kph in fourth and sweeps you back on the pit straight to start another lap..."