McLaren Racing Director Eric Boullier has revealed when the British team would ideally like to have decided their 2018 engine supplier by, as a continuation of the Honda partnership appears increasingly likely.

The Woking outfit has had better form in recent races, culminating in a double-points finish with their cars at the Hungarian Grand Prix this past weekend, but performance on most circuits remains quite some way off what is expected, meaning alternatives are still being considered for next year.

"Technically you could change an engine in 12 weeks," Boullier told Sky Sports in Budapest. "If you want to do the very best job then the latest is September if you want to do the best design."

The list of alternatives would only appear to consist of one name, however, that being Renault after Executive Director Zak Brown seemed to rule a widely speculated return to Mercedes and the remarkable prospect of a tie-up with Ferrari just over two weeks ago at Silverstone.

"We're a big team that knows how to win races and championships so I think most of the teams, while it's a shame to see where we are, they like us where we are," Brown claimed.

"They don't want to get us too close to them which is understandable."

A switch to Renault would also appear unlikely due to probable opposition from Red Bull, as well as the French manufacturer not wanting the prospect of two teams out-performing their works outfit.

Therefore, despite Sauber recently ending a deal with Honda for 2018 and, as a result, causing some to question the Japanese carmakers own future involvement, it seems faith will have to be kept in them by McLaren, something that could very well decide whether Fernando Alonso stays or goes at the end of the year.