The McLaren driver had a disappointing time on Saturday as he was eliminated from Q1 after struggling for pace around the Suzuka circuit. He had been due to start from 17th.

With Honda aware that Button needed to have new powerunit components fitted before the end of the season – potentially at Austin – it made sense to make the switch early because there was very little to lose at Japan.

Button will have a new internal combustion engine, MGU-H, MGU-K, turbo, control electronics and energy store – earning him a 35-place grid penalty.

The change will include Button switching to the updated engine block that Alonso is racing for the first time this weekend – which was aimed at improving reliability rather than lifting performance.