By Alan Baldwin
SILVERSTONE, England (Reuters) - Daniel Ricciardo's run of five successive podium places looks in danger of ending after the gearbox on his car was replaced ahead of the British Grand Prix, incurring an automatic five-place grid penalty.
Gearboxes must last for six races and the one in Ricciardo's Red Bull, which was swapped out before Saturday's final practice, had not done so.
The Australian won in Azerbaijan in late June and finished third in Austria two weeks ago.
It was his second grid penalty of the season, after a similar five-place drop in his home race in Melbourne in March. He started from the pit lane on that occasion and failed to finish the race.
Mercedes rival Valtteri Bottas, who won in Austria from pole position, also has a five-place penalty for Sunday's race after a similar gearbox change.
Ferrari's Sebastian Vettel leads Mercedes' Lewis Hamilton by 20 points after nine of 20 races. Hamilton, who had a five-place drop in Austria, is chasing his fourth successive British Grand Prix win and fifth in total.
There has been increasing debate this season about the fairness of penalizing a driver for mechanical problems beyond his control, although Formula One has always been a team sport.
(Reporting by Alan Baldwin; Editing by John O'Brien)