F1 boss suggests two grands prix will lose calendar slots for 2020

A new race in Vietnam has already been confirmed for next April, while a deal has been agreed but not signed with Zandvoort for a May date for the return of the Dutch Grand Prix.

Carey also intimated that the schedule will expand beyond 21 races after 2020 due to the level of demand.

Although he did not name the venues, Carey said that two deals have been agreed with circuits whose contracts finish this year, while confirming that F1 is still talking to the other tracks whose deals are up for renewal.

Monza has already revealed that it has extended its contract, which leaves Silverstone, Hockenheim, Mexico and Barcelona as tracks out of contract. The Spanish event is widely expected to be dropped.

"We're in the process of finalising our 2020 race calendar," Carey said in a call with financial analysts.

"We have agreements in principle on two renewals, and are actively engaged on three other renewals.

"In addition we have already announced our race in Hanoi, and construction has begun on the track [illustrated below] and facilities.

"It will be a street course that is one of the most unique and challenging racetracks in the world, with 22 corners and a couple of long straights, the design of which we have been intimately involved with. I was in Hanoi a few weeks ago, and the excitement was palpable.

"In addition to Hanoi, we also have an agreement in principle to add another new circuit to our calendar in 2020.

"We've not finalised the number of races in 2020, but we currently expect it to be 21, the same as 2019.

"Obviously the maths means that we will not be able to renew all our current races."

Carey underlined that a lot of thought goes into shaping the calendar and deciding which races to include or leave out - and suggested that some "churn" or change was good for the championship.

"We value our partnerships with our existing promoters, however we believe it is important for our fans and the growth of our sport and business that we both add exciting new locations, and manage a limited level of churn," he added.

"We're in the fortunate position of having more demand than supply, but recognise that we need to manage that dynamic in a thoughtful manner.

"The factors we consider in deciding on a race include the quality of the track for great racing, and the location as one that captures the world's imagination; the level of fan and broader support and enthusiasm in the host city and country; the historic importance and future potential of the track and race; the global balance of our schedule; and a number of other factors.

"We clearly have demand for more than 21 races in 2020, and do expect that number of races in a year will increased slightly after 2020."