Ferrari and Red Bull are to test from Friday next week at Barcelona, whilst their rivals begin testing on Thursday.

The two teams, who have agreed the move with the opposition, have different reasons for the date switch.

Ferrari was first to make the switch, although unexplained appearing to confirm - despite the Maranello outfit's insistence to the contrary - that it is off the pace and seeking time to find a solution.

Red Bull, which is believed to be keen to try out new components away from the watching eyes of (most of) the competition, approached Ferrari and asked if it could it n changing dates, the Italian team agreeing.

Speaking earlier, Bernie Ecclestone appeared to confirm that Ferrari has a problem, though he was reluctant to shed further light. "I know what the problem is," he told reporters in London. "It's not difficult to fix, so I think you're going to find that they are going to fix it quite shortly."

Lotus, who pulled out of this week's test after just one day, is aiming to be back in Barcelona for the start of testing on Thursday. However, it's understood the Enstone outfit is to ask permission to join Ferrari and Red Bull on Monday 5 March, thereby giving it an extra day, having missed three days of testing this week.