Button gets grid penalty for his F1 return

The penalty makes it near-certain that Button will be at the back of the grid for his one-off F1 return to cover for Fernando Alonso's Indianapolis 500 effort.

Honda announced on Saturday morning that a problem had been discovered in the MGU-H on Button's car following Thursday's practice sessions and that it required both the MGU-H and turbocharger to be replaced.

As both were the fifth such components fitted to the car this season, that exceeded the four-per-year limit and prompted the penalty.

Although Monaco is Button's first appearance of 2017, such penalties are decided by use-per-car so Alonso's problems earlier in the season were factored in.

Honda also changed the internal combustion engine, MGU-K, MGU-H and turbocharger in Stoffel Vandoorne's car before Thursday and Saturday but those change "were scheduled in order to control the mileage".

Only the MGU-K was new, and is Vandoorne's third of the year, with the other parts re-used from previous races, so Vandoorne does not receive any penalties.