Jaguar Land Rover boss David Smith has stepped down, the car maker announced today.
The chief executive's departure comes after talks between union bosses and Jaguar Land Rover stalled following a failure between the two parties to reach an agreement over workers' pay and conditions.
However, the company - now part of Indian group Tata Motors - said Mr Smith's exit was not linked to the breakdown of discussions.
A spokesman for the company said: "We are disappointed the discussions ended without agreement, but his departure is not linked to the talks."
Jaguar Land Rover is planning to make changes to pay and pensions for new starters, but talks with unions broke down after six days of discussions last week.
The group said director Ravi Kant had taken over from Mr Smith on an interim basis until a permanent successor is appointed.
The firm remained tight-lipped on the details of his departure, saying only that "it's a confidential matter between him and the company".
But a spokesman added: "The company would like to thank David for his efforts in the role and for his service to Jaguar Land Rover over many years."
He has acted as chief executive since June 2008, but has links with the group dating back to 1983, when he worked at Ford, which previously owned Jaguar Land Rover.
Tata bought the group from Ford in 2008 for $2.3bn (1.62m).
Informal talks between union leaders and the company had taken place before Christmas following the publication of the firm's strategic review in September.
The company sat down with Unite last week to discuss the review, including proposed changes to pay and pensions.
Part of the package tabled by Jaguar Land Rover was to guarantee 8,000 production jobs until 2015.
However, the package of proposals was not accepted by the unions and agreement with the company was not reached.
It is understood union leaders and bosses at Jaguar Land Rover will return for further talks and industrial action is not imminent.