Two former Ferrari drivers are not sure when the great Maranello team will rise to the very top of Formula 1 once again.

Gerhard Berger raced for the Italian marque in the era immediately preceding the famous Michael Schumacher days, where the German won five consecutive world championships in the first half of last decade.

When asked if Sebastian Vettel can now do the same, Berger told Bild am Sonntag: "In Formula 1, you never known. It may happen quickly, or it may not happen at all.

"What I do know is that I worked at Ferrari for many years and I was in exactly the same situation as Vettel is now - sometimes I won, but mostly I did not.

"There is always a lot of pressure from above. Jean Todt managed to lead a team with Michael Schumacher and Rory Byrne and Ross Brawn that shielded this pressure from top to bottom and so it was a very successful time. But it seems to me as it Ferrari is back where it was with me - Italian confusion."

Another driver who knows the highly political Ferrari of the pre-Schumacher days well is Alain Prost, who joined in 1990 but a year later was fired for criticising the car and team.

When asked by Minute-Auto.fr about Ferrari's current struggle to return to the top in F1, Prost said: "I can sum it up in one sentence: real stability at Ferrari is very difficult.

"We see that when there is this nervousness, this is not a team that manages it in the best way.

"This is a team that needs confidence to move forward and become again the steamroller that it was in the time of Todt, Brawn and Schumacher."

Ferrari remain second to Mercedes in the standings following the Canadian Grand Prix.