Red Bull team principal Christian Horner has ramped up his feud with Zak Brown by accusing McLaren of changing the rear wings on their cars. It was first blood to Horner and co on Friday at this weekend’s US Grand Prix, with Max Verstappen taking pole position in sprint race qualifying on Friday.

Title rival Lando Norris could only manage fourth place, a blow to his hopes of eating into the Dutchman’s 52-point lead in the drivers’ standings in Austin.

But the action on the track has thus far been overshadowed by the ongoing feud between Horner and Brown, that has intensified amid the battle between their teams for both the drivers’ and constructors’ titles.

Since arriving in America, Red Bull have been criticised be rivals after it emerged they had been using a special ride height device to adjust the bibs on their cars under parc ferme conditions. Despite the FIA stating no rules has been broken, McLaren have been among the more vociferous in questioning the lack of sanctions.

Asked about the comments of Brown and co, Horner implied the Britsh team were making noise to mask their own discrepancies. "I feel that it's sometimes to distract from perhaps what's going on in your own house, then sometimes you try to light a fire somewhere else,” he told Sky Sports.

Asked “Are you saying the McLaren have something dodgy going on?" the Englishman replied: “I mean, there's an awful lot of noise about rear wings, and McLaren had to change theirs yesterday."

At that point, Horner was corrected by his interviewer, but after being told: “They say that's not the case,” he refused to back down. "Oh really?” he said. “Okay. I mean, it's part of Formula 1, and I'm sure there will be other stuff that comes up between now and Abu Dhabi."

Brown has since hit back, insisting McLaren’s rear wing complies with the regulations. “Absolutely,” said the American. “Our rear wings passed every single test. We’ve made some small modifications, as have some others. So that’s a non-issue.”

And trying to put the heat back on Red Bull, he argued their ‘bib trick’ benefitted the floor’s air tunnels on their vehicles. “I think on the floor, if, and I say if, because I don’t know, it’s used in an inappropriate manner, then it is definitely a performance advantage,” he said.

Tensions have simmered between Horner and Brown all season long, with the latter taking regular shots over the internal scandal that has engulfed the reigning constructors’ champions. After an investigation, Horner was cleared of inappropriate behaviour towards a female employee, with the defendant later having an appeal dismissed.

During the investigation, Brown said: “McLaren holds themselves and all the men and women at McLaren to the highest standards. Red Bull corporation, it appears, has launched an investigation and all we hope and assume is that will be handled in a very transparent way as FIA and Formula 1 has said.”