The Dane came up on Raikkonen while preparing for a decisive last-ditch effort in the final qualifying segment at the French Grand Prix, having not yet set a laptime in a session disrupted by his teammate Romain Grosjean's crash.

He got past Raikkonen but the Finn raced him on the main straight as his final timed lap began and got ahead once more into Turn 1, only to finally back out of his attempt.

Magnussen carried on but could do no better than ninth, 2.9s off the pace, and was left fuming at Raikkonen's actions, asking his Haas team: "What the f**k is he doing?"

Asked about his anger on the radio, Magnussen said: "[I was] very upset. Because, what is he doing?

"He f****d all his laps, he had fuel for I don't know how many laps, everyone else has fuel for one lap, so to begin with I thought he would box 'cause he f****d his lap.

"And then he tries again immediately the lap after. Overtakes us, backed off again - then surely he's going to box. But then he tries again.

"So it's three laps in a row that he tried to push and it makes no sense. There's no way to predict what he is going to do.

"And then he obviously overtakes me into Turn 1, and f***s my lap, and doesn't even complete his lap."

He added: "I don't know, if you're that confused, just try not to get in the way of anyone else."

The FIA stewards confirmed they would be investigating whether Raikkonen "unnecessarily impeded another driver", and both he and Magnussen were summoned to the stewards.

"I don't know if what he did is against the rules, but surely he is impossible to predict," Magnussen railed.

"And also he is stopping at Turn 14, then he's pushing, then he's stopping, that's erratic driving in my mind, but I don't know if it is in the stewards' mind."

Raikkonen was up against it in the closing minutes of qualifying, as a sideways moment on his first run had left him only sixth.

Unable to put together a better lap in the end, he conceded "the last try was just a mess" - while Magnussen insisted he was being "desperate".

"It's frustrating what happened. I don't think it was necessary," Magnussen said.

"I think he just had no idea what to do and he was desperate to get a lap, he hadn't done a lap, he f**ked all his laps. He was desperate."

Additional reporting by Oleg Karpov