Klien thankful to Red Bull

His swift departure came after he turned down an offer from Red Bull to race in Champ Car next year. He will be replaced by Robert Doornbos for the final three years of the year.

Klien is now chasing a deal with another team and is believed to be pushing hard to land the third drive at Spyker-Midland for the Chinese Grand Prix.

"Since I needed more time to explore the F1 options, I regretfully could not accept the Champ Car option by the date given," explained.

"I appreciate Red Bull Racing's decision to annul my current F1 contract... This will allow me to continue the current, ongoing discussions regarding my F1 options as an independent driver, free of any contractual obligations.

"I am now fully focused on the talks for my existing F1 options. I assume that I can announce my decision on the options by the end of the 2006 F1 season."

Klien could be given the Spyker-Midland car as a try out in Shanghai with a view to securing a full-time race seat in 2007.