George Russell has revealed his safety concerns if Formula 1 bans tyre blankets for the 2024 season, warning "there will be crashes, I have no doubt about it".
However, tyre supplier Pirelli insists its prototype blanket-free slick tyres are raceable and has put the onus on F1 drivers to adapt their driving style to get the dry tyres up to temperature should the ban go ahead.
Tyre blankets enable teams to heat their tyres to 70*C for two hours before a session, providing drivers with better grip at the start of a race or when coming out of the pits.
In a bid to improve sustainability, Pirelli has been developing tyres that do not need pre-warming. Blanket-free wet tyres were introduced earlier this season - and raced for the first time at the Monaco GP - while drivers have been testing the dry-tyre versions.
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Russell took part in the most recent test in Barcelona after the Spanish Grand Prix and he outlined his concerns ahead of the Canadian GP.
"In hindsight, it probably wasn't tested in the right conditions at the right circuit," Russell said of his run in Barcelona.
"I think if you go to a circuit such as Barcelona, which is quite an aggressive tarmac, it was 40-odd degree track temperature, fully rubbered in from the race weekend. The tyres were very sketchy coming out of the pit lane, but by about Turn Five on the out lap, it was at a respectable level.
"But if I compare that in contrast with the start of the year, when I did one run in Jerez in 10-degree track temperature, it was extremely difficult getting out of the pits.
"And if I'm being totally honest, I don't think we as a sport are at a position yet to bring these tyres into a racing scenario.
"I would be very concerned for all the mechanics in the pit lane during a pitstop, I'd be very concerned for the out lap from a race in cold conditions. There will be crashes, I have no doubt about it.
"And I think there's a lot of work, expense, development going into these tyres. I feel like that could be put elsewhere."
A final decision on whether tyre blankets are allowed in 2024 will be made next month. Red Bull, Haas and Williams are participating in a final test after the British GP and all 10 teams will then take part in a vote on whether to ban tyre warmers or not.
Charles Leclerc took part in the same test as Russell and echoed the Briton's fears of how blanket-free tyres will perform at cooler races.
"I have to say that in the conditions that I had during the test, it was good, and it went well," the Ferrari driver said.
"But yeah, in lower temperatures, I don't know. I haven't tested these tyres in lower temperatures and that's where the big question mark is.
"So, very difficult to answer whether I will be happy to go. I would like to maybe test those tyres in different conditions and then see whether they are raceable in all conditions. But again, it was a positive test with the conditions that we've had in Barcelona.
"You've got four or five corners where it's very tricky. Where the tyres need to get into temperature. When you are alone on track it is not that much of a problem. But of course, if you are racing other cars, then it becomes very, very difficult to manage.
"If it remains four or five corners, even in low conditions, then it's something that we could consider. But obviously with very low conditions, I expect this to be much longer, this warm-up period, and this then could become difficult."
Pirelli: Drivers need to adapt driving style
Pirelli insists it has no safety concerns from the data collected in the tyre tests so far, with the company's F1 chief engineer Simone Berra saying drivers need to change how they approach their out laps on them.
"We consider the tyre raceable because otherwise, we would not have proposed it for the evaluation," he told The Race.
"Yes, they are raceable. The first sector could be tricky but apart from that it's OK.
"Obviously drivers need to think about the fact that not using the blankets is different than today, so they need to approach the out lap in a different way.
"In cold conditions, it could be trickier to bring the tyres up to temperature but it's just a matter of doing the first portion of the lap [cautiously].
"In the first sector, generally we can see much more difference compared to other sectors because already sector 2 and 3 are in line with the lap times with the blankets, so it's just a matter of managing the first few corners.
"But in terms of safety, I don't see from the data any specific risk.
"You need to change the way you are driving in the first lap, you have to adapt the driving style to protect the tyres because you can generate graining if you push too much in the first corners and the tyres are not up to temperature.
"I respect driver opinion, that's for sure, but obviously there will be differences compared to the old product and the [current] tyre management."
Brundle: Better ways to be environmentally friendly than banning tyre blankets
In his latest column, Sky Sports F1's Martin Brundle highlighted how a tyre-blanket ban would have likely stopped drivers going out on dry tyres during the changeable conditions of qualifying at the Canadian GP and stressed his belief there are better ways to drive sustainability in F1.
Brundle wrote: "A wet, albeit temporarily almost dry, qualifying served up some thrills and surprises for a nicely scrambled grid. There was a two-lap window to fit dry tyres in Q2 which the likes of Alex Albon in his Williams and a few of the other usual suspects anticipated well, but Sergio Perez in his Red Bull and Charles Leclerc in his Ferrari simply did not.
"It was a good reminder for those who want to stop tyre warmers and use F1 cars to heat them up instead, that such moments will disappear if they are banned. Nobody will venture out on cold slicks in anything like those conditions, and nor will they in a race either until it's certain they can stay on the track and generate heat rather than smash the cars to pieces.
"There are better ways to be environmentally friendly rather than fuelling an F1 car for a few extra laps to heat the tyres every run rather than directly applying a very efficient blanket system which heats specifically the tyre and wheel."
Wolff: What is the reward? | Fallows: Overarching idea is sound
Mercedes boss Toto Wolff said he would vote on the tyre blanket ban in line with what Russell, Lewis Hamilton and Mick Schumacher fed back to him.
Wolff said: "At the end, we want a good show and we need to listen to the drivers and see what all their opinions are. I tend to agree with the drivers that why are we making experiments that can potentially create a safety hazard?
"What is it we want to achieve? Risk and reward - my understanding in my life is that risk and reward need to be well measured and I don't think there is a great reward in making experiments with Formula 1 cars with drivers in there for the fun of it."
Aston Martin technical director Dan Fallows is more positive about the proposal, saying: "From my point of view, I think the overarching idea of it is sound.
"I think there is a great push towards sustainability in F1 and making sure that we don't have to carry excess baggage around the world and use more energy than we absolutely have to. So I think it's absolutely laudable what they're doing. And I think the idea is absolutely sound.
"Really, in terms of the technical aspects of it, it's something that it's a vision that the FIA had, and it's something that Pirelli needs to do from their point of view. But yeah, we're very supportive of the idea of it. It's obviously just a technical challenge, which we need to play our part in helping out to see whether we can achieve it."
Red Bull boss Christian Horner said he would "reserve judgement" on the decision until after Daniel Ricciardo has conducted the test at Silverstone next month, but suggested focus should instead be on finding sustainable ways to power the tyre warmers.
"I don't think it's what the drivers want. Let's reserve judgement until we've done a test ourselves," Horner said.
"But my fear with these things is that when you think you're going to achieve something simplistically that would create better racing, that there will then be a whole load of effort go into trying to heat tyres very quickly, on out-laps and so on, that could drive a lot more cost in.
"Everybody has tyre blankets, they do the job. I think what we should be looking at is sustainable ways of powering those tyre blankets as opposed to removing them."
Red Bull seek to continue their winning run in 2023 as they return to their home track for the Austrian GP - watch live on Sky Sports F1 from June 30-July 2. Get Sky Sports