Mercedes has ruled out the possibility of supplying Red Bull with Formula One engines.
Honda's decision to leave the sport at the end of the 2021 season means Red Bull and its sister team Alpha Tauri will need to find a new engine supplier to power their cars from 2022 onward.
There are only three other engine manufacturers in F1 -- Mercedes, Ferrari and Renault -- but while it is not yet clear what Red Bull will do, Mercedes has ruled out a supply deal.
"No," Mercedes team boss Toto Wolff said when asked whether there was any chance of supplying Red Bull. "For various reasons, but the main thing is we are supplying four teams, including us.
"We are almost in a state that we can't make PU for all of us, so there is no capacity. But I have no doubt Helmut [Marko, Red Bull's F1 adviser] will have a Plan B, as he said, and probably doesn't need to rely on any of the PU suppliers."
One possibility that has been rumoured is Red Bull buying Honda's existing engine design and developing it itself, but team principal Christian Horner said nothing had been decided.
"We need a competitive engine," he said. "With the situation we have been in in the past, we need a competitive engine and we need to be in a competitive position. Cost is a factor in that; regulations are a key factor in that; and we have to explore all the options in terms of availability of supply, who would be able to supply and obviously under what conditions. It's not a normal customer team transaction to supply a team like Red Bull."
Ferrari did not rule out a supply but said Red Bull would need to make the approach first. "It is something we need to start considering now, I think we have not decided [anything yet] as first I think it will be down to Red Bull to first of all look at us and ask for a supply," Ferrari team principal Mattia Binotto said. "They're a great team, no doubt, but I think supplying them is a lot of energy somehow which is required, but something on which we need to consider.
"We have no position yet, but it is certainly something we need to take our time to think about and have a decision. I think timing-wise it's very little time because we need to organise ourselves, 2022 is just around the corner, so as we said, it was sudden news from Honda and I think now we need to consider something that was not being considered a few days ago."
The most likely candidate seems to be Renault as it will not have any engine customers once McLaren switches to a Mercedes supply deal next year. The FIA rules state that no team can be left without an engine supply and that the governing body will automatically pair any team without a deal to the manufacturer with the fewest customers.
However, Renault team boss Cyril Abiteboul confirmed that no talks had taken place yet with Red Bull as of Friday. "I can confirm that I have not been contacted by Red Bull in relation to an engine supply," he said. "I don't think it is a question of whether we are open or not open.
"We know the regulations, when you are a participant to the sport, you have to accept the rules; it's part of the sporting regulations, we know what that is. We know the details, in terms of timing, there is still quite a bit of time before we get there.
"I can't imagine that they don't have a Plan A or Plan B, and I think we are very far in the pecking order of the alphabet before they call us again."