By Alan Baldwin
LONDON (Reuters) - Alfa Romeo's return to Formula One shows the value of the sport and suggests Ferrari will not follow through on threats to leave, according to Red Bull principal Christian Horner.
Alfa Romeo is part of the Fiat Chrysler group whose chief executive Sergio Marchionne is also the head of sportscar maker Ferrari, who are Formula One's most successful and glamorous team.
The Swiss Sauber team announced on Thursday that the Italian marque was returning to the sport as their title sponsor after a 30-year absence, with the team to be known as Alfa Romeo Sauber F1 from next season.
"They (Alfa) come under the same management as Sergio so I can't believe he'd have brought Alfa Romeo in for Ferrari to be leaving in a couple of years," Horner told Reuters.
"I think it demonstrates that Formula One is obviously working and creating the recognition, otherwise the group wouldn't have brought the Alfa brand into Formula One," he added.
Alfa has a long history in motor racing, from pre-World War Two days to the winning the first two Formula One drivers' championships in 1950 and 1951. Enzo Ferrari worked for them before building his first car in 1947.
Marchionne warned in November that Ferrari, who were spun off from Fiat Chrysler at the start of last year, could walk away if the sport took a direction contrary to the company's interests.
He will attend an Alfa Romeo Sauber presentation in Arese, near Milan, on Saturday.
Horner, who was speaking at the launch of the Aston Martin R-Motorsport sportscar team in London on Thursday, has previously dismissed Marchionne's comments as 'bluster'.
"Formula One needs Ferrari and Ferrari needs Formula One. It's a marriage of convenience in many respects but both entities ultimately need each other. And we certainly want Ferrari in Formula One," he said.
"A Formula One with Ferrari in, it's one of the biggest brands in the world and they are a great team to compete against."
Sauber will use Ferrari engines next year, along with the U.S.-owned Haas team and Ferrari's works outfit.
Red Bull are one of three using Renault power units but the future is clouded by uncertainty, with the engine regulations set for a change in 2021.
Aston Martin will be Red Bull's title sponsors next season and chief executive Andy Palmer has spoken of the possibility of the British sportscar company eventually building an engine if the rules provide for a much cheaper and simpler unit.
"Liberty (the Formula One owners) are very keen to reduce costs to simplify the engine and to attract new brands into Formula One," said Horner.
"Aston are extremely keen to have an increased presence and I think we're all in a little bit of a holding pattern at the moment waiting to see what are those regulations going to be.
"You'd have to partner with a specialist, and research and development cost resource restrictions would have to be in place in order for there to be a playing field that they could compete on," he added.
(Corrects second paragraph to make clear Ferrari is not controlled by Fiat Chrysler group)
(Reporting by Alan Baldwin, editing by Christian Radnedge)