Hamburg  - Spain's Jaime Alguersuari is to replace New Zealander Brendon Hartley as reserve driver for Red Bull, the Formula One team announced Wednesday.

The 19-year-old, who became the youngest ever British F3 champion last year and is currently competing in the World Series by Renault, will not only act as stand-in driver for Red Bull drivers Sebastian Vettel but also for Red Bull's sister team Toro Rosso.

The change takes effect from the German Grand Prix on July 12.

"With the ban on in-season testing, Red Bull views the appointment of a third driver as part of its Young Driver training programme, allowing a driver to follow all activities of the F1 teams over a race weekend, attending technical briefings and listening in on the pit to car radio conversations," said Red Bull in a statement.

"Having benefited from this experience over the first half of the year, Hartley will now concentrate on his own racing programme in the European F3 series."(dpa)