Eric Boullier has suggested that McLaren cannot wait much longer for Honda to improve their engines, as the team risks damaging their brand by producing further poor results.

The Woking-based constructor's 2015 campaign has been blighted by a lack of pace and reliability since switching from Mercedes engines last winter.

However, the McLaren racing director has admitted that results must improve soon if the team are to retain its status as one of the leading players in Formula 1.

He is quoted by Motorsport as saying: "The damage is easy to understand. You establish your brand by your success and repeated success and I think McLaren, by the number of wins and championships, has clearly established its brand as excellence."

"Commercially it does hurt because obviously a lot of people and a lot of companies are interested in joining us.

"But some people in their organisation may question the lack of results actually and I don't think we can wait for very long any more."

McLaren have not won a Grand Prix since Lewis Hamilton's triumph at the Circuit of the Americas in 2012.