The Spaniard failed to complete a lap in qualifying at Spa-Francorchamps after his McLaren stopped on track with a power unit failure.

The problem appears to have been a repeat of the issue he suffered in free practice with low oil pressure, and Honda admitted it had been a mistake to try to run in qualifying with the same engine.

Honda F1 chief Yusuke Hasegawa said: “This morning we saw some low oil pressure, so we had to stop the session. We checked the data, and we adjusted the oil pressure.

“We thought we could do it, and take a risk to join qualifying. Actually my judgement was a mistake and it was not good, so we have to change the engine for tomorrow.”

Two failures across Spa weekend

The oil pressure problem comes after Alonso had to abandon his original upgraded engine on Friday because of a water leak from the turbine.

When asked why Honda had suffered a double failure after a season when reliability has been greatly improved, Hasegawa said: “So far we believe it is a coincidence and not related to the new-specification update engine. But we have to be mindful that we have not had enough time to check the engine.”

Honda engineers are currently meeting to decide which components will be changed on Alonso's power unit for the race – and this will decide how big his penalty is.

Progress made

Despite the disappointment over reliability, Hasegawa said he was encouraged by the performance potential the new engine had shown – with Button getting through to Q3 on a power track.

“In Spa we thought we will have a very hard time,” he said. “Of course we are not satisfied with the current situation but we could almost achieve the same level as Hockenheim, which is very good for the engine update, I think.”