Speculation that McLaren and Honda could be set to split is intensifying ahead of this weekend's Canadian Grand Prix.

With the Japanese carmaker notably struggling since re-entering Formula 1 with McLaren in 2015, the once-great British team are reportedly now considering breaking their contract and buying Mercedes engines for 2018.

Spain's Marca sports newspaper says that new team executive Zak Brown has reached 'his limit' with Honda, while Diario Sport says that a 90-day deadline has been set.

Another Spanish sports daily, AS, said that McLaren's deadline will actually come sooner than that.

"The first grand prix after the summer break (Belgium) is the limit for Brown and [Eric] Boullier, although they already expect to be competitive by Hungary," the report says.

"But the deadline is Spa. If they are not at a proper level in Belgium, comfortably entering Q3 and fighting close to the top three, McLaren will decide to resume talks that have already begun with Mercedes."

McLaren have yet to register any points in 2017.