Toro Rosso will continue to be the official Honda works team next season, even if Red Bull decides to cut ties with Renault and sign up with the Japanese manufacturer.
Toro Rosso technical director James Key revealed that the team's raised status would remain intact, even if the world championship-winning senior squad joined the Honda camp in 2019.
"We have a separate deal to whatever Red Bull would have," Key insisted. "If Red Bull came on board it could only be added to that for us."
"It's not a combined contract," he told RACER magazine this week. "It's an STR contract for three years as a works deal."
This marks the first time in the team's history that it has had works team status in Formula 1. Key is keen to make the most of it, but also sees the advantages of the senior race team coming on board.
"It's an opportunity to work closer together on certain aspects which would be good for both teams," he said of the possibility. "So in that respect I have no issues with it."
Renault has until May to decide what it wants to do about engines in 2019. It will be looking at how Toro Rosso starts the season with its new Honda power units.
However Key insisted that his team hadn't been a 'sacrificial lamb', testing the ground for Red Bull. He revealed that the Honda deal had been very much their idea from the start.
"We've been keeping up with Honda for several years. We've very much wanted to work with them," he said. "It was a hope that we could do that. When the possibility arose, it was actually very possible for us.
"We felt we could have a very amicable relationship with them potentially, because we have a kind of an understanding there. So far that's been very much the case."
But Key conceded that the decision to move to Honda power in 2018 had needed to fit in with Red Bull's overall strategy.
"It was a decision made jointly in some way, I suppose," he conceded. "The teams are owned by the same company and that was a company decision in that respect.
"What Red Bull Racing do is ultimately their decision in the end," he said. "But if we can share an engine supplier it would be very good.
"It's not a tricky decision or anything like that, no."