Dr Helmut Marko has slammed Red Bull's door on Fernando Alonso.
Alonso, who will have his second sabbatical year in 2020, has indicated that he may return in 2021. Flavio Briatore, involved in his management, says the Spaniard would only return for Ferrari, Mercedes or Red Bull.
Alonso, 38, has claimed to have had several periods of negotiations with Red Bull throughout his career, but Marko says a collaboration for 2021 is not going to happen.
"As things stand today, Fernando Alonso's return with Red Bull is absolutely impossible to imagine," the top team official told Motorsport-Magazin.com.
"There are two reasons for that. First, there is the relationship between Alonso and Honda, which I think is quite broken.
"And second, our entire Formula 1 structure is based on our junior program, which means that our young talents move to the top category of racing.
"If we signed Alonso, he would be the oldest driver on the grid. That would contradict our entire philosophy," Marko said.
"But as we use a Honda engine, it is impossible anyway."