Engine expert Gilles Simon has parted company with Honda as the Japanese manufacturer's problems continue.

Simon, who began f1 career with Renault subsequently headed to Peugeot where he was responsible for the engine which took the French manufacturer to Le Mans success.

Following Peugeot boss Jean Todt to Ferrari in 1993, assisting Paolo Martinelli he took over as head of the legendary marque's engine department in 2006.

In December 2009, he was recruited by Jean Todt, now FIA president, to join a working group investigating new energies and environmentally friendly technology in motorsport.

His recruitment by Honda in 2013 was seen as a positive sign, no doubt influenced by McLaren, due to the Japanese manufacturer not normally recruiting from outside the company.

The reason for his departure is unclear with neither Honda or Simon willing to comment, indeed it is understood he has been placed on six months gardening leave.

Despite a positive step forward last year, McLaren suffered a difficult opening test, a badly designed oil tank compromising the first day's running and a series of engine issues further compromising running.

While Honda boss Yusuke Hasegawa, who had already admitted that the introduction of a new engine might mean issues for the team, has confirmed that he is concerned at whether the issues can be resolved for the start of the season, McLaren team boss Eric Boullier has admitted that the situation "is not good enough".

"We had issues that we absolutely did not expect to have," he admitted, "and neither did Honda. It is fixable, but it was not the plan to have these issues.

"They are not really serious, as there are no fundamental issues with the design." he insisted.