McLaren bosses had concerns the problems caused by the troubled Honda partnership would trigger some "very good people" to leave, Racing Director Eric Boullier has admitted.

The Woking-based outfit had to endure another difficult season in 2017, finishing ninth in the Constructors' Championship and only managing three more points than in the first year back with the Japanese manufacturer in 2015.

That lack of progress would prove to be the final straw for McLaren, with the two sides agreeing to split in September and the Frenchman claimed that action shouldn't have surprised Honda based on the warnings they were given

“I went to the management, showed them the data and told them that we cannot accept another year like this,” Boullier told the official Formula 1 website.

“We had a tough first year with Honda, we had a tough second year, and had expected progress good enough to get us back to where we belong – but Barcelona showed that we would go backwards and that was absolutely not an option.

“I obviously warned them about the consequences of another year of no results, where you keep everybody afloat," he added. “We have a new team, which has been reconstructed in the last three years: new people, very good new people – competitive people who used to win – and the danger was we’d lose them.

“The perception of a team is still very much based on drivers because they are the faces of the team, but for me, the real danger was losing those people. That was the discussion at the very beginning of the season.”

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A double podium at the first race of the V6 hybrid era in 2014 remains the only top-three finish for any of McLaren's drivers since Jenson Button claimed their last F1 win in Brazil five years ago.

But expectations now are very high that, that will change when they start using Renault engines from next season, with Boullier already suggesting the hard work has been done in producing a car that can challenge for victories.

“When you look at what we have achieved in terms of car performance – chassis performance – we know that we are back on the podium, at the top,” he claimed. “That for me is a huge reward – that we have achieved this in difficult circumstances. The other positive I take from the past three years is that the team is really joined now.

“We have been suffering so much for three years but at the same time, nobody has left the team. Everybody agreed that this team will be winning again. There is a huge trust and confidence in what we are trying to achieve and because of that we have gone up, up, up, keeping developing this car.”