Christian Horner says only a shock Lewis Hamilton retirement would stop Daniel Ricciardo signing a contract extension with Red Bull now.
Ricciardo's future has been the subject of much speculation this season, the final year of his existing contract. The Australian was strongly linked with Mercedes and Ferrari and made no secret of his desire to one day drive alongside Hamilton, but he appears set to stay with the Red Bull team he's driven for since 2014.
"We're moving very much in the right direction," Red Bull boss Horner said when asked about the contract negotiations. "We've now got to the point where there is a desire from both sides to continue the relationship, so it's just a matter of now really going through the detail and coming to a conclusion which will certainly be done prior to the summer break."
Ricciardo's chances of moving away from Red Bull appeared to be linked to the status of the grid's two Finns, Mercedes' Valtteri Bottas and Ferrari's Kimi Raikkonen. Both are also out of contract at the end of 2018 and seemed to be the most likely candidates to be replaced by Ricciardo.
However, Mercedes appears to be happy to retain Bottas beyond 2018, while Ferrari is likely to turn to its exciting junior prospect Charles Leclerc, who has impressed so far in his rookie campaign at Sauber, if it decides against retaining Raikkonen.
"I think that had Mercedes put a serious offer on the table, or an offer on the table, he would have been potentially interested," Horner added. "He's 29 years of age now, obviously his focus is on... he's in the halcyon years of his career and he's impatient to try and challenge for a world title.
"So I think he would have had his head turned in the event of a Mercedes or a Ferrari offer but I think those two teams look pretty set where they are. So Red Bull he's grown up with, he's taken his time to look around, and he suits the brand extremely well. As a brand ambassador he's a hugely popular driver, he's very popular within the team and he's got a very good technical understanding and sensitivity within the car."
Horner believes the recent confirmation of Red Bull's new deal with Honda, which will start in 2019, has also helped convince Ricciardo to stay.
"I think obviously one of the things he was waiting to understand was where we were going with engines as well. I think he's seen and understood the decision-making behind the route that we've gone.
"So as I say, hopefully the rest of it becomes a formality, unless Lewis announces his retirement at the British Grand Prix this weekend."
Hamilton is also out of contract, but has been in negotiations with Mercedes for most of the year. A new deal is expected to be confirmed in the coming weeks.