Sao Paulo Mayor Joao Doria insists the future of the Brazilian Grand Prix at Interlagos is safe until 2020, despite the likely sale of the legendary circuit in the coming months.

One of Formula 1's most anticipated and historic races has been under threat in recent years due to the rising cost of hosting the event and calls to upgrade facilities at what is officially called the Autodromo Jose Carlos Pace.

With concerns over the financial viability of the circuit, owned by the city of Sao Paulo, it is to be sold to a private company with F1 tyre supplier Pirelli and even former CEO Bernie Ecclestone, who has regularly questioned the sustainability of the Brazil race, believed to be interested.

Despite the pending change in ownership, Mayor Doria insists there will be no impact on the future of F1 racing at Interlagos.

"This will probably be the last Brazilian Grand Prix with the city still in control," he is quoted by local publication Globo. "Next year, the circuit will be auctioned but while there will be a new owner, the contract with F1 will be strictly obeyed until 2020."

Indeed, Doria added: "Our wish is then that F1 will continue in 2021, 2022, and for a long time. The idea is that it continues for three or four decades."

This year marks 45 years since the first Brazilian Grand Prix at Interlagos back in 1972, then the circuit was just under twice the length of the current layout with a long outer loop which curled back into the infield which is still mostly used today.

The current incarnation, which sees the outer loop now turn down into the infield section at the famous Senna 'S' has been used in F1 since 1991.