Red Bull is edging closer to a decision on whether it will put its own road car into production.
Speaking to Autocar at the Goodwood Festival of Speed, Horner said the project "is still being talked about," and "hasn't been ruled out for the future."
The firm’s chief technical officer Adrian Newey is already said to be working on potential designs for the car. “It’s something that Adrian is keen to do as a legacy project," said Horner.
The prospect of a Red Bull road car first emerged in 2013, when Horner said he wanted to use the team’s expertise “outside of F1” to grow the brand.
More recently, Newey confirmed to the Guardian newspaper that Red Bull was looking for technical partners for the project - though the main partner is still likely to be Infiniti, with which Red Bull already shares some aspects of road car development.
Red Bull and Infiniti worked together on the Q50 Eau Rouge, a performance version of Infiniti’s executive saloon designed to show how F1 technology can be applied on the road.
Already driven in prototype form by Autocar, the Eau Rouge produces 552bhp from its twin-turbocharged 3.8-litre V6 engine - the same unit used in the Nissan GT-R. If it makes production, the Eau Rouge will rival the Audi RS6, Jaguar XFR and BMW M5.
In the short term, said Horner, Red Bull will continue to work with Infiniti to develop the Japanese brand’s road-based offerings. Although Horner didn't comment on the liklihood of that relationship being extended with Red Bull's own plans, it is open to change as the F1 team continues to decide to carry on working with Renault after 2016, when its current engine agreement runs out. Infiniti is part of the Renault-Nissan Group.