Eric Boullier is convinced McLaren could still unlock 'seconds of potential' from the MP4-30 this season.

McLaren has just five points to its name after nine races, an indication of how much it has struggled since switching to Honda power ahead of 2015. Fernando Alonso was 2.7 seconds off the pole time in Silverstone but racing director Boullier is adamant there are big strides to be made, citing the team's current inability to use MGU-K every lap.

"If we can unlock the potential we will maybe be fighting - with some luck - for a podium," Boullier told the official F1 website. "If you can deploy your MGU-K power on the straights on every lap, that is worth a lot of time. Today we can't do that.

"We all know the level of commitment from McLaren - that doesn't need to be discussed. But the positive is the level of commitment of Honda, and the fact we know that our cars have not tenths but seconds of potential that can be unlocked. We cannot physically use that because we have reliability issues, but if we overcome those we will be able to make major steps forward, believe me."

Boullier says the lingering fear of reliability issues is having an impact on engine performance.

"It is not completely down to only power - it has also to do with the driveability of the engine, which has proved very difficult and complex to manage so far. Let me give you an example: we all have the same power in terms of electrical power, but some engines are doing a better job in recovering the energy. That is why you see a difference in qualifying and the race.

"We are not able today to unlock the full recovery potential because if we do it creates reliability issues - and that hurts us in terms of performance. But it is there! We just have to find the right remedies to unlock it."

However, he is not willing to lay all the blame at Honda's doorstep and admits McLaren can make improvements to the MP4-30.

"If we had more downforce we would be faster as well. The car is balanced, yes, and the concept that we have put in place is working - but in the end we need to be better everywhere!"

Despite predicting a big gain, Boullier does not think that step forward will necessarily happen at once.

"It is not that easy - it is not switching on something in the car and it works. A consequence could be that if you fix one problem you jump ahead not by tenths but by half a second; another problem - another half a second..."