Red Bull team principal Christian Horner has performed an apparent U-turn by retracting his claim that Lewis Hamilton’s new Mercedes is illegal.

Hamilton’s Mercedes team are running a radically revised machine for the final test in Bahrain before next Sunday’s season opener in the Gulf Kingdom.

The focus is on the Silver Arrows’ virtually non-existent sidepods, designed to provide greater airflow, improving downforce, and effectively making the car go faster.

In an interview with German publication Auto Motor und Sport on Thursday, Horner said: “From our point of view, Mercedes went a step too far.

“That doesn’t correspond to the spirit of the regulations. For us, these wings are illegal.”

But speaking 24 hours later, Horner denied that he suggested Mercedes had bent the rules.

“Comments have been quoted that certainly were not made,” said Horner.

“Obviously Mercedes have come up with an extreme and different interpretation but to answer whether we think it is legal or not – yes, absolutely. It looks like it ticks all the boxes.

“As far as we are concerned, the Mercedes car looks as though it complies with the regulations.”

While Horner’s comments would appear to rule out a Red Bull protest, Hamilton’s Mercedes could yet be outlawed if eight of the grid’s 10 teams – the so-called super majority – believe the concept is not within the spirit of the revamped regulations.

However, Horner added: “There is not really anything that defines the spirit of the regulations.

“It either complies or it doesn’t and it not really for us to judge. The FIA has access to all of the drawings, and a design like that would surely have been submitted to them in advance.”

Away from the noise surrounding Mercedes’ new sidepods, Ferrari have quietly impressed in testing, with Horner describing the Italian giants as the “form team”.

Horner added: “For me the car that appears the most settled on track is Ferrari. They have looked extremely competitive.

“Mercedes have not fully shown their hand and will no doubt be a huge factor in this championship. Hopefully we can be in there, too.”

Horner’s remarks come after British driver George Russell, racing alongside Hamilton at Mercedes this season, said Ferrari seem to be in the strongest position.

But Ferrari driver Carlos Sainz said: “That is typical Mercedes and typical George, to hype up the others before coming to the first race and blowing the competition away.

“If it was the first year, I might have believed them, but they have done it for several years now. So I don’t believe that.”

Although times count for little in testing as teams run different strategies, Alpine’s Esteban Ocon set the pace in the morning session on the penultimate day in Bahrain.

The Frenchman finished 0.090 seconds clear of Ferrari’s Charles Leclerc, with world champion Max Verstappen third for Red Bull.