Cape Town - Formula 1 could still have a British Grand Prix without Silverstone being involved; that's a warning to the circuit from F1's commercial boss Sean Bratches. 

Silverstone, which is owned by the British Racing Drivers’ Club, is out of contract after next year's grand prix having exercised a break clause for financial reasons. 

The BRDC have not giving up on Silverstone hosting the race down the line, they only want to negotiate a better deal. 

But while Liberty Media are keen to preserve the sport's historic races, Bratches has warned that the British Grand Prix could move to a new venue in order to keep it on the calendar. 

"We're a 68-year-old entity and the nature of grand prix racing is that it is dynamic," he said in a Formula One question and answer. 

"Silverstone was the first grand prix, but we haven't raced at Silverstone all those 68 years. 

"The race has been held at Brands Hatch and other venues. 

"Nothing is immutable in this sport in terms of where we race. 

"We do value certain races highly and we do what we can to preserve racing there, but we are a business. 

"We are a public company and we have a lot of stakeholders and shareholders and we're trying to marry what's best for fans with running a successful business."

While the British Grand Prix has been on the F1 calendar since the very beginning in 1950, Silverstone used to share the race with Brands Hatch before becoming the sole host in 1987. 

Bratches reiterated earlier statements from Liberty Media about wanting more street races which they feel allows them to bring F1 closer to the people. 

He added: "We look at it in three ways. Firstly, we want to preserve the heritage races, they are very important to Formula 1 and they are very important to fans. 

"I'm talking about the Silverstones, the Spas, the Monzas of this world. 

"Then we have a set of street races and hybrid street races, where we race in parks and on city streets, such as Melbourne, Montreal and Mexico City.

"The third segment features purpose-built facilities such as Shanghai, Austin, Texas and Bahrain. 

"Beyond that we are looking to identify further street races, so this race [Vietnam] is a further step in terms of our vision." 

Earlier this week Liberty Media announced that Vietnam would join the calendar in 2020 with a street race.