The McLaren driver badly damaged his front wing after striking the drain cover at the exit of Ste. Devote at the end of the session.

It appeared that Nico Rosberg had pulled the cover up after running over it, puncturing the left rear wheel of his Mercedes in the process.

Nico Rosberg, Mercedes AMG F1 W07 Hybrid with a punctured rear wheel Photo by: XPB Images

It was not immediately clear in the wake of the incident what Button had hit, but photos of the broken cover soon emerged.

The size of the piece of metal was substantial, and the fact that it was flying around will likely renew the debate over closed cockpits in F1 to prevent drivers from being injured from such debris.

F1 race director Charlie Whiting visited the scene straight after the session, and track officials were summoned to weld the cover back down again before the start of a slightly delayed GP2 practice session.

The incident provided a reminder of what happened in 2010 when Rubens Barrichello suffered a puncture after striking a similarly placed drain cover that had worked loose there during the race.

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