Wirth admits Virgin behind schedule

Wirth said the intention had been to bring aerodynamic developments to Barcelona next week, but with Lucas di Grassi and Timo Glock only able to complete 144 laps between them over the past four days at Jerez, Virgin will now have to keep focusing on reliability work in the final test.

"It has been a character-building week, that's for sure," said Wirth. "Despite our best efforts to cure the hydraulic problem which has beset our entire test, this was simply not achievable with the components that we had available in the field.

"The specific problem is that we have been losing hydraulic oil at a rate which has limited the number of laps we can achieve on each run and so we look forward to receiving updated parts for the Barcelona test, which we expect to fully resolve the problem.

"Having said that, we will now need to continue focusing on reliability work when we would have liked to introduce our Bahrain-specification aerodynamic updates. The revised programme means we will be reserving our full set of aero warpaint for the first race."

But Wirth added that while the test delays were a blow, he was very optimistic about the VR-01's pace.

"On a positive note, despite these issues, we have actually completed a lot of good race preparation work and it is satisfying to see the car's potential with minimum set-up changes or development, bearing in mind that we have consistently run with a healthy amount of fuel," he said.

"Indeed, none of our lap times have been achieved with anything close to qualifying fuel and therefore we are not letting the frustrations in one specific area overshadow what has generally been an encouraging start to our development programme."