LOTUS Renault team principal Eric Boullier has revealed Nick Heidfeld’s failure to adequately serve as leader resulted in his axing.

The Enstone-based team won an initial hearing on Wednesday to replace Heidfeld with reserve Bruno Senna for tomorrow’s Belgian Grand Prix and subsequent race in Italy.

However, driver and team are to head to the High Court on September 19 to resolve the dispute, as Heidfeld believes he is contractually obliged to see out the season.

Although Heidfeld is two points ahead of teammate Vit-aly Petrov in the drivers’ table, Boullier feels he had no choice but to tell him he was not wanted.

“We reviewed our performance and level of motivation, a number of things over the summer, and we chose a new direction,” said Boullier.

“There was also an opportunity to assess Bruno as a driver, and this is why we have moved on. It is nothing to do with money.

“Every session, every weekend, the media have jumped on me asking why Vitaly is faster than Nick.

“I was not very happy with his speed and overall performance as an experienced driver. Nick is a nice guy, but leadership didn’t work.

“When you are slower than Vitaly most of the time, it’s difficult for him to push the team and set up himself as team leader.

“I admit the car is not good enough, we have not developed it well enough, so we have made mistakes as well.

“When you have a negative spiral, it’s complicated to stop it, so I had to change something within the team, something with the drivers to shake up and wake up everybody.”

Boullier has revealed Heidfeld refused to settle out of court, only for Renault to win on every count in the initial hearing.

Meanwhile, Senna had a spin in practice yesterday at turn nine between Rivage and Pouhon, crunching the rear of his car into the barrier.