Struggling McLaren are free to fit new engines for both Fernando Alonso and Jenson Button without any penalty at this weekend’s Hungarian Grand Prix.

The two former world champion drivers have suffered massive grid penalties in recent races after needing to have replacement Honda power units put in their cars.

A regulation change at a meeting of Formula One’s World Motor Sport Council this month has permitted new manufacturers to take one new unit for each driver without any sanction.

Spaniard Alonso and Briton Button had been penalised since exceeding their original allocation of four engines when they took a fifth in Austria.

The tight and technical Hungaroring circuit is expected to give the McLaren team an opportunity to secure an improved result because it is not a track that demands outright power.