The Briton, who has battled cancer, recently stepped down as president of the British Racing Drivers' Club, which owns Silverstone.
But Warwick, 63, only stepped down after Silverstone last year triggered the break clause in its F1 contract, which could see Britain host its last race in 2019.
Talks are now taking place with Liberty about a new deal.
"The grand prix is too expensive, we're losing money and that's why we triggered the break clause," he told the Jersey Evening Post.
"Britain is the home of motor sport. Does that mean there will always be a British grand prix? Absolutely not.
"Of course we want a British grand prix and for it to stay at Silverstone, but we want it to be affordable so that we can make just enough money to reinvest in the circuit. We can't do that under the present deal," he insisted.
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