Former Williams technical director Paddy Lowe, who was on a leave of absence from the British outfit, has stepped down from the team's board of directors with immediate effect.
Lowe took time off from Williams just one week before the 2019 season kicked off in Melbourne.
The British engineer's leave of absence came in the aftermath of production issues that had forced Williams to delay the roll-out of its FW42 for pre-season testing in Barcelona.
But it was also clear from the outset that the performance level of the team's 2019 contender had fallen well short of expectations. A deficit that followed the shortfall of Lowe's previous design, the Williams Fw41 which led to a dismal 2018 season for F1s third most successful team on the grid.
Lowe, a Williams shareholder who joined the team from Mercedes in 2017, has now permanently departed the Grove-based squad.
"After a period of careful reflection I have reached the decision that I will not return to work at Williams," said the 57-year-old engineer in a statement released by the team on Tuesday.
"I wish all my previous colleagues the very best to meet the challenges ahead, which I am sure they will do. I would especially like to thank the Williams fans who are so supportive."
Claire Williams said: "We understand and respect the decision Paddy has reached and wish him well for the future".