Williams' new development driver Alex Lynn has confirmed his split from Red Bull's high profile junior programme.
Last year, as he powered to the GP3 title and the highly coveted Macau GP win, the 21-year-old Briton was named as a contender to replace Jean-Eric Vergne at Toro Rosso for 2015.
Ultimately, the F1 seats went to two other Red Bull-backed rookies, Max Verstappen and Carlos Sainz jr.
Lynn has subsequently signed up with Williams and been promised a day in the FW37 at the post Spanish grand prix test in May.
He has now confirmed in the local Essex newspaper Braintree and Witham Times that he has left Red Bull's high-profile driver programme headed by Dr Helmut Marko.
"My attachment to Red Bull has now come to an end," said Lynn. "It was a very amicable decision for both of us.
"Fair enough, they made their decision over appointing their F1 drivers and I knew that there would be no opportunity there to race with Red Bull in the next two years and that would be too late for me.
"They appreciate that. They were happy for me to stay, but they said they knew they couldn't stop me from chasing my dream," Lynn added.