McLaren F1's Alonso and Button get 'free' new Hondas for Hungary

As part of a regulation change approved by the World Motor Sport Council earlier this month, any new manufacturer entering the sport will be granted an extra power unit per driver.

That concession has been applied to 2015 returnee Honda as well.

Alonso and Button had already been penalised for exceeding their original allocation of four engines when they took a fifth in Austria and so the free unit concession is being applied on use of the sixth.

The rules divide the power unit into six elements - the internal-combustion engine, the MGU-K, the MGU-H, the turbocharger, the energy store and control electronics - and so the next individual change of those can be done for free.

With the tight and twisty nature of the Hungaroring likely to provide McLaren with one of its best chances of the season to gain a strong result, the alliance has chosen to make the change on both cars now.

Button and Alonso have one 'old' engine apiece that could still be used again.

Investigations continue on Alonso's fifth Honda following his crash with Kimi Raikkonen and on Button's fourth after a sensor failure at the same race with the Japanese firm hopeful both can be used again.

Honda has used two development tokens of its allocation, with the remainder expected to be used aggressively soon after the summer break.