F1 cost cap row: Lewis Hamilton questions Red Bull's 2021 upgrades | 'Transparency always essential'

Lewis Hamilton has questioned Red Bull's 2021 upgrades and believes if Mercedes had matched them last season it could have "changed the outcome of the championship".

Hamilton did not accuse Red Bull of breaking the budget cap but admitted he had been thinking about the issue throughout last season.

The seven-time world champion believes the FIA must be transparent in their decision making and backed them to make the right decision.

• FIA delays budget cap decision until Monday; Denies information leak
• 'Minor' breaches made in F1 budget cap regulations

Red Bull are one of the teams rumoured to have breached the spending cap, although that was vehemently denied by team principal Christian Horner during the previous round of the championship in Singapore.

"What I can say is I remember last year in Silverstone we had our last upgrade and fortunately it was great and we could fight with it," Hamilton said, speaking ahead of this weekend's Japanese Grand Prix.

"But then we would see Red Bull every weekend or every other weekend bringing upgrades. They had, I think, at least four more upgrades from that point.

"If we spent £300,000 on a new floor, or adapted a wing, it would have changed the outcome of the championship naturally because we would have been in better competition in the next race if you add it on.

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"So, I hope that that's not the case. I do believe Mohammed [Ben Sulayem, FIA president] and the FIA will do what is right with whatever they find out."

The FIA announced ahead of the Japanese GP that confirmation of whether or not any of the sport's 10 constructors had breached the $145m spending limit in 2021 would be delayed until Monday, October 10, with two teams rumoured to have gone over that cap.

Sky Sports News understands there have been no 'major' breaches of the cap - an overspend of more than five per cent - and that any punishment would be in line with those set out for 'minor' breaches of overspending by five per cent.

Possible sanctions for minor breaches include the deduction of constructors' and drivers' championship points and a suspension from one or more stages of a competition.

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Limitations on the team's ability to conduct aerodynamic or other testing, or a reduction in their overall cost cap going forward are also options.

Red Bull driver and reigning world champion Max Verstappen, who could seal a second title at Suzuka this weekend, insists he is not worrying about the outcome of the FIA's cap certification or any possible sanctions his team could face though.

"I think we have our reasons to believe we're good, that's what I've been told and we'll find out on Monday," said Verstappen, speaking to Sky Sports in response to Hamilton's comments.

"It's also something between the team and the FIA, it's not really up to me, I'm here to drive fast and try to give the best result to the team."

Seven-time world champion Hamilton has faith that the sport's governing body are committed to integrity, and hopes that proves to be the case with the cost cap.

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"Transparency is always very important, particularly in particularly with all the fans that tune in and travel around the world," Hamilton said.

"I think it's important for all of us, plus all the people that are working, the thousands who work in the sport, I think it's important to have transparency throughout the organisation.

"And accountability is something that we always have to hold true too. We've seen in previous years of the sport where things have been dealt with in the background, I don't think that's the new way forward with the new way of working with Mohammed.

"I think integrity is very important to him and as is F1 nowadays with a new management, so I think we have good people in place. I hope that we get the right governance."

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George Russell echoed Mercedes team-mate Hamilton's views in Thursday's pre-race press conference at Suzuka and underlined his belief the FIA will take the right approach with any team determined to have spent over the cap.

"We know we can bring more performance to the table if we had more money to spend and it's as simple as that that," Russell said.

"I trust in Mohammed and the FIA to bring an appropriate punishment for anyone found guilty of the charges accused.

"It should be quite straightforward, and you would expect the amount that is taken off for next year's budget and probably a bit more on top of that as a punishment, but let's wait and see."

Herbert: Punishment for breach will set precedent

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Sky Sports F1's Johnny Herbert...

"I can understand from a driver's point of view. You put your heart and soul into trying to put in the best performances you possibly can within the cockpit of the car to go as fast as you possibly can. Then you hear all these rumours that maybe somebody has over-spent, and we all know if that is the case, there's going to be an advantage from that. Then when that advantage is something you hear about, and maybe know about, that just makes it that much harder to sort of accept certain situations that have happened in the past or are happening at the present time.

"I completely understand what his (Hamilton's) thinking may be. But we're not accountants, we don't really know the whole issue that has really gone on so we need to wait and see exactly what it is.

"I think whatever happens, if there is somebody that has breached, then it's what they do as a penalty, because it would be the precedent that would be set for the future and that will be the thing teams will be looking at. Because that would then give them the direction for what they can do in the future.

"It does mean a big thing to everybody here, to exactly what penalty is put on a particular team that is found guilty of that.

"It's going to have to be tough because the only way you're going to be able to try and stamp it out is to be tough and say 'if we get to this point once again it's going to be a harsh penalty'. Hopefully, that's something that will come our way because I think that's what everybody will expect watching back home as a Formula One fan."