Barcelona, Thursday: Red Bull Racing have come forward with a statement attempting to explain their sudden surge in performance, seen on the first morning of testing at Spain’s Circuit de Catalunya.

Accidental: The Red Bull RB6, complete with sheet

Although variable fuel loads, different testing strategies and “sandbagging” (defined as a McLaren going slowly for reasons the team aren’t prepared to admit to) make it difficult to read too much into testing times, Red Bull insist their improvement in pace – which put Mark Webber at the top of the time sheets this morning – is real and easily explained.

“It’s quite embarrassing really,” team principal Christian Horner told journalists during the lunch break at Barcelona. “It turns out that, during the testing at Jerez, we were so concerned that no other team steal our diffuser designs that we accidentally ran for the whole week with a big sheet covering the rear of the car.

“Obviously this had quite a big effect in terms of performance and airflow, which means that a lot of the data we gathered in Jerez is now pretty useless. It has set us back a bit, but we’re confident we will still be the best team of all come Bahrain.”

Sources in the paddock indicate that Mercedes GP in particular are frustrated by the revelations, having brought a big sheet of their own to Barcelona in the hope of emulating some of Red Bull’s success.

Secrecy is nothing new in F1, and is being practiced to varying degrees by other teams this season. USF1 has so far adopted the most extreme solution, being so cautious about its radical transverse gearbox that it has done all of its testing so far this year without a car.