F1's three-day young driver test kicks off at Silverstone

Daniel Ricciardo's crucial is set to be the biggest story of the test, with the Australian having the chance to make his case to land the vacant seat alongside Sebastian Vettel for 2014.

While a strong performance in this test will not the seat, Red Bull will have a number of specific performance areas on which to evaluate Ricciardo.

The Australian was set to run on Wednesday afternoon, but following a late schedule change will now run on Thursday instead, straight after morning duties with Toro Rosso.

Ricciardo will test instead of Mark Webber, who will not run at all. Teams are permitted to run race drivers, but only to a strictly-defined Pirelli schedule that covers two half-days - which are being taken by Ricciardo and Sebastian Vettel.

Highly-rated Red Bull Jr Antonio Felix da Costa opens up for Red Bull on the first day.

This could be a defining test for GP2 ace James Calado, who will have his first outing for Force India this morning before handing over to Paul di Resta for the afternoon.

Calado has been earmarked for potential Friday morning practice outings later in the year, but the team will make a final decision on him once he has driven the car during this test.

Meet the young F1 testers

Daniel Juncadella, winner of the 2011 Macau GP, will make his F1 test debut for Williams, with GP3 championship leader Tio Ellinas making his bow for Marussia this morning.

The other main story of the test will be the new specification of Pirelli tyres, which will be used from the Hungarian Grand Prix onwards.

Teams will run the soft, medium and hard compounds (no team selected the super soft), with an extra five sets of tyres added to the previous year-long testing allocation of 100 given to each team to cover both pre-season testing and the young driver running.

Pirelli has also allocated seven extra sets of tyres (three hard, to medium and two prototype hards as tried in free practice for the Canadian and British GPs) for use by race drivers.

"The experience of the race drivers is bound to bring a lot and we look forward to hearing their feedback," said Pirelli motorsport director Paul Hembery.

"We're not expecting the new specification of tyre to feel considerably different to the previous specification to drive and the general characteristics should be similar.

"Nonetheless, there will be plenty of useful work that the teams should be able to carry out within the next three days."

Race drivers are only allowed to run on the proviso they run to plans supplied by Pirelli.

All teams except McLaren plan to run race drivers at some point this week, with Marussia's Max Chilton set to be the only driver to run for his regular team today.

Mercedes has been banned from taking part in the Silverstone test, but will still have access to Pirelli's tyre data from across the three days.

Silverstone test line-up as announced by teams so far:

* The driving schedule will be confirmed each morning