Red Bull Racing boss Christian Horner says he has no regrets about criticizing Renault this season - and admits that in part, he was trying to send a message to the French company's board and CEO Carlos Ghosn.
Horner, who has harbored doubts about Renault's commitment, wanted to give the management a wake-up call.
"The Renault board are quite distant from what is going on," Horner told FOX Sports. "It is not like Dieter Zetsche, who attends quite a few races, or Sergio Marchionne, and so I guess part of being vocal was also to get those messages back to the Renault board - that there are some issues here, and they need to be resolved.
"I think that things were said ultimately on both sides - of course it is never good to conduct your business in public, but it was really born out of frustration more than anything else."
Horner insisted he also had no regrets about going public.
"It is very easy for others to pick up and use whatever excuse is convenient, Horner said. "What you have to remember is, this is a competitive business. As far as I am concerned, I have only ever told you the truth.
"When I have been asked a question, I have given you an answer, and if you look at actually what I have said, I don't think there is anything particularly unfair in the comments that have been made. I think inevitably it's been born out of frustration - comments that either Dietrich, or Adrian, or Helmut have made."
Horner admits to being frustrated when Renault opted not to accept technical input from Ilmor's Mario Illien that had been arranged by Red Bull - a decision that has now been reversed for 2016.
"Renault went through some management changes towards the end of last year, and there was an awful lot of talk going on," Horner added. "We introduced Mario Illien to them, and there was resistance to use Mario initially. We created an engine group to support. There was not the smoothest of relationships between Milton Keynes and Viry, and out of that - obviously grew frustration.
"I think there was always a reluctance to fully embrace Red Bull as a technical partner, and there was a difference of opinion technically on where the weaknesses of the engine were. We couldn't influence the technical direction of the development.
"Mario developed a concept for Renault, and Renault in parallel ran their own project and the outcome of which was the D-spec. I never felt that Renault fully embraced the technical capability and simulation capability that we tried to offer. It was very clear early on that Renault weren't happy being just a supplier. From the back end of last year, they have been looking at becoming an entrant again."
Horner denies that Red Bull pushed Renault too hard throughout the season.
"I don't think so. I think that they are quite an established and conservative organisation, and of course our DNA is that we want to push. We want to make progress.
"Obviously, a lot of promises were made over the last quarter of the year and the close season of 2014 into 2015. So inevitably, expectation rose. It was frustrating to see us further away, and in fact behind where we finished the season in 2014 going into the beginning of 2015."
He admits that Renault's inherently conservative approach has held the company back.
"I think in some respects, it possibly has," Horner said. "It is good to hear that they are looking at a bit of a restructure."
Meanwhile, Horner says that another side effect of Renault's winter problems was that issues with the chassis were not immediately apparent, although later the team was able to get on top of them.
"I think with regard to the engine, we were running old specification engines through the winter, and we had quite a lot of issues - reliability and particularly driveability. That was masking quite a lot of the chassis issues.
"The front wing changes and nose changes over the winter actually seemed to affect us more than others, but they were a little bit masked early on by the major issues that we were having with the driveability. It was only once that started to improve that we could say, "hang on, we've got some things that need tidying up", which the team quickly got on top of."
