Fernando Alonso says he would like McLaren to make a decision on its engine supplier quickly so the team can start focusing on its 2018 package as soon as possible.
The Woking team is considering a split with current engine partner Honda following another disastrous season that has resulted in two points scored in the first 10 races.
Having a competitive engine in 2018 is seen as a key factor in McLaren's hopes of retaining Alonso, the Spaniard's contract ending this year.
The two-time champion says he would support whatever decision McLaren makes, but is hoping the team can decide sooner rather than later.
"It's up to them, but definitely the sooner you make a decision the better preparation you have for the following year so I guess they will try to make it an early decision," said Alonso after retiring from the British Grand Prix.
"Obviously I would support whatever decision they make.
"For me, for the team, it's Hungary in 15 days' time. A good opportunity, so that's reality. The other things are just dreams."
Alonso hinted McLaren had no doubt the weakest part of the package was the Honda power unit.
When asked if McLaren would be fighting at the front if it had a Mercedes or Ferrari engine, Alonso said: "Who knows. It's difficult to guess, to imagine different combinations of cars and engines, et cetera, but I think we identified very clearly what we are missing - so if we can improve that, we can be competitive.
"But this is definitely not in the near future so we need look at reality and reality is in 15 days Hungary is a good opportunity for us, so hopefully we can do better there."
Alonso had started the British Grand Prix from the bottom of the grid after taking engine penalties, but retired from the race with a suspected fuel pump issue on lap 32.
He admitted the retirement was less painful as he believes he was not in contention for a points finish.
"Tough time. Unfortunately we had another issue today. A fuel pump, I think, which hopefully didn't damage the engine and we can use the engine in the future. A difficult weekend, starting last, and following a group of cars it was a difficult race.
"We were not in the points, so today's DNF is a bit less painful because we were not able to take points."