Red Bull chief Christian Horner criticises Mercedes boss Toto Wolff ...

Mercedes team principal Toto Wolff and Red Bull counterpart Christian Horner have accused each other of acting in self-interest in a developing row over Formula 1's 2026 engine regulations.

As Max Verstappen dominated another Grand Prix in Austria over the weekend, the beginning of a potentially highly significant debate was playing out in the background.

Despite not coming face to face, Wolff and Horner used their media briefings to trade barbs and opposing viewpoints on whether changes should be made to the new regulations coming to the sport in 2026.

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The ground-breaking engine changes were agreed upon and approved by all F1 teams in August 2022, but Horner says that he - and others in the paddock - believe tweaks are required.

With a long way to go until the result of the regulations are revealed in the opening weeks of 2026, the exchange between two of F1's heavyweights in Austria is likely to just be the start of major debate.

What is happening in 2026?

The rule changes in 2026 are aimed at making Formula 1 even more sustainable, driving forward innovation to make the car industry as a whole better for the world in the race against global warming.

The regulations will look to ensure the following:

There will be three times the electric power - the aim is for the MGU-K to produce around 350kW in 2026 (the electrical component of the power unit currently produces 120kW of energy)More than 1,000 horsepower engines with less fuel used - in 2026, F1 is aiming for each car to use just 70kg of fuel during a Grand Prix, compared with 100kg in 2020Cheaper engines - There will be an engine-specific cost cap to encourage more car manufacturers to get involved in finding innovative solutionsNo new carbon from fossil fuels will be released into the atmosphere

The new regulations, albeit still a long way from being introduced, have already had a hugely positive impact for the sport.

German manufacturer Audi have signed up for a works team, Japanese engine supplier Honda have decided to remain in the sport, and Ford have partnered with Red Bull on their 2026 engine.

What are Horner's concerns?

Amid reports that F1 teams have been questioning the FIA over the impact the 2026 regulations will have on car performance and racing, Horner came forward with his concerns in Friday's press conference at the Austrian Grand Prix.

Autosport have reported that teams are concerned that the combination of combustion engine and electric power may not produce enough energy for cars to be able to run flat out for an entire lap.

The Red Bull boss, whose team have won all nine races (and both Sprint contests) this season, says just a five per cent swing towards more combustion and less electrical power could resolve the potential issue.

"I think that perhaps where we need to pay urgent attention, before it's too late, is to look at the ratio between combustion power and electrical power," Horner said.

"(We need) to ensure that we're not creating a technical Frankenstein, which will require the chassis to compensate to such a degree with moveable aero and reduce the drag to such a level that the racing will be affected - and that there will be no tow effect and no DRS because effectively you're running like that at all points in time.

"Plus, with the characteristics of these engines, that the combustion engine just doesn't become a generator to recharge a battery.

"We still have two and a half years, and I think if there is a slight redress it would then create potentially a better platform for the chassis. Otherwise, the chassis regulations that are undefined yet and uncommitted, we're going to be trying to cater for those compromises.

"You have got to look at the thing holistically from both the technical point of view, and most importantly what is F1.

"F1 needs to be wheel-to-wheel racing. We can't afford to lose that challenge and have drivers downshifting on the straights to regenerate batteries.

"I know the FIA taking it very seriously, and they're looking at it very closely as the simulations become more advanced."

Wolff: There is zero chance | Horner is frightened

Responding to Horner's comments a day later, Wolff didn't pull any punches as he said there was "zero chance" of the regulations being changed.

"That's not going to happen, zero chance, capital letters," Wolff said.

"So I don't know why these things are even coming up. We've developed those regulations over many years with all the auto manufacturers being involved. It was a compromise that attracted Audi to finally join the sport, for Honda to stay in there - the best possible case that one could imagine for F1.

"Is it challenging? Our chassis designers are saying 'well, how are we going to do this?' Yeah, super (challenging). But zero, these regulations are not going to change any more, they're not going to be postponed any more, because the world needs to show innovation around sustainability, we need to reduce emissions, and we are super excited."

2026 will see the debut of the first engine made by the Red Bull Powertrains division, who until then are operating a power unit supplied by Honda.

Wolff suggested that Horner's comments could be motivated by Red Bull struggling with the development of their engine.

"I think what frightens him more maybe is that his engine programme is not coming along and that maybe he wants to kill it that way," Wolff said.

"So you always have to question what's the real motivation to say something like that."

Horner hits back: Wolff focused on self-gain

Having watched Max Verstappen seal his fifth successive Grand Prix victory on Sunday, Horner offered a stinging response to Wolff's comments.

"Unfortunately that's typically Toto where he's just focused on self-performance," the Red Bull boss said. "My interest is actually about the sport rather than self-gain.

"It's still way too early to say who's going to have a competitive or uncompetitive engine in 2026… for me the most important thing is from a sports point of view, that we all have a collective responsibility to work with the FIA and the commercial rights holder to ensure that the product is as good as it can be, otherwise we've all failed."

Asked whether Wolff's point about changing the regulations having attracted new brands to the sport was a reasonable one, Horner responded: "The regulations are a hybrid of what was originally intended, and of course it's only as you work through a set of regulations that you find out where their limitations are.

"I think the FIA is being very responsible in terms of doing its due diligence, and I think certain teams share very similar opinions to that of our own. I think they have a capable team, I think they're aware of what the challenges are."

Sky Sports F1's live British GP schedule

Thursday July 66pm: The F1 Show

Friday July 78:40am: F3 Practice10am: F2 Practice12pm: British GP Practice One (session starts 12:30pm)2.05pm: F3 Qualifying3pm: F2 Qualifying3:40pm: British GP Practice Two (session starts 4pm)

Saturday July 89:15am: F3 Sprint11:15am: British GP Practice Three (session starts 11:30am)1:10pm: F2 Sprint2:15pm: British GP Qualifying build-up3pm: BRITISH GP QUALIFYING5pm: Ted's Qualifying Notebook

Sunday July 98:10am: F3 Feature Race9:50am: F2 Feature Race11:50am: Porsche Supercup1:30pm: Grand Prix Sunday - British GP build-up3pm: The BRITISH GRAND PRIX5pm: Chequered Flag: British GP reaction6pm: Ted's Notebook

Next on the F1 calendar is the big one, Silverstone. Don't miss the British GP live on Sky Sports from July 7-9