Bernie Ecclestone has vowed to fight after Her Majesty's Revenue and Customs decided to tear up a settlement deal relating to a family trust.
Ecclestone has previously under investigation by the British tax collectors and reached a settlement back in 2008.
However, HMRC now says that deal is invalid, relating to evidence that came to light during his German bribery case.
"The tax and interest demanded as a result of the decision is over 1 billion pounds," Bloomberg reports judge Kenneth Parker as having said.
Ecclestone, though, is set to fight it.
Speaking to Autosport in the Monaco paddock, he said: "I have never had anything to do with the trust.
"I'll be fighting this all the way. I've paid all the taxes I've ever had to pay.
"I could do whatever I do from here [Monaco], or Switzerland.
"I've a Swiss residence and the Swiss say I'm a Swiss domicile, so it would be easy to do it from there."