Honda has given an explanation about the extent of its struggle so far in 2017.

The signs are growing stronger by the day that McLaren have now decided to dump their hapless engine supplier mid-contract.

"The rhetoric has changed," former technical boss Mike Gascoyne told Sky Sports News. "It just sounds like a decision has been made."

Some think that dumping Honda, and switching to customer Mercedes power, could be a desperate effort by the Woking team to hang on to their frustrated top driver Fernando Alonso.

Asked if Honda or Mercedes power would make a difference, Alonso said: "I think it doesn't make any change to my decision."

Nonetheless, it is believed that the final straw for McLaren was the days before Montreal, when Honda informed the team that a planned upgrade would not be delivered on time.

Honda chief Yusuke Hasegawa is quoted as saying by Osterreich: "We have not managed to get the right conditions on the test bench.

"Now we need to understand why there is a difference between the test bench and the track."

The season continues in Baku next weekend.