Nissan executives are making contingency plans for separating from Renault, Automotive News Europe quoted the Financial Times as saying. The backup plans included Nissan returning to independent efforts in engineering and manufacturing as well as changes to the board of management at Nissan, the Financial Times reported.

The plans for independence had been accelerated by the Japanese company since former chairman Carlos Ghosn fled Japan, where he was accused of financial crimes, to his childhood home of Lebanon, the paper reported. Bloomberg also reported that Nissan’s consideration of splitting with Renault arose from concerns that its relations with its longtime French alliance partner has turned sour.

The feasibility of any potential separation is unclear, the reports noted, given that Renault is Nissan’s largest shareholder and the French automaker has been pushing for a repair of ties between parties. The companies are trying to find solutions to problems with the long-standing partnership and launch new industrial projects, people familiar with the situation told Automotive News Europe.

Among the projects from the Alliance started during the Ghosn era are due to see production reality this year. The 2019 Tokyo Motor Show saw the emergence of the Nissan Ariya, a concept electric crossover built on an all-new joint EV platform featuring a dual-motor, AWD layout, and a Renault equivalent is expected arrive in 2021.

Renault chairman Jean-Dominique Senard stated his doubts in a French radio interview last November about the partnership’s longevity when he was appointed to replace Ghosn. “If in 2020 we don’t extract the whole virtuous potential of this alliance, I will consider that I and my teams have failed,” Senard said.

Relations between the two Alliance partners were further strained when the proposed merger with Fiat Chrysler Automobiles had failed to materialise, though the roots of the tensions between Renault and Nissan date further back. A major point of contention since 2015 was the equal division of costs for research and development into new technology and products, sources close to Nissan told Reuters.

The arrangement “did not compensate Nissan’s work properly; Nissan’s engineering output was 40% better, meaning Nissan engineers on average produced 40% more than their Renault counterparts in a given amount of time spent on a job,” one of the sources said, and when measured more strictly, Nissan’s output was in some cases double that of Renault’s, the source added.

Financial prospects for both Renault and Nissan have been a struggle since Ghosn’s arrest on allegations of financial misconduct, resulting in his removal from positions at Nissan and at Mitsubishi, and eventually resigned from his roles at Renault.