Brown attended IndyCar’s double-header on Belle Isle 10 days ago along with racing director Eric Boullier and Gil de Ferran. The two-time CART Indy car champion and 2003 Indy 500 winner acted as Fernando Alonso’s advisor for the two-time F1 champion’s Indy debut in 2017, and has been appointed by McLaren in a consulting role within Formula 1 but also on any potential IndyCar project.

The rumors of McLaren’s full- or part-time return to IndyCar grew also when, as well as meeting with team owners, Brown and Boullier were spotted with Sprint CEO Michel Combes. Sprint sponsorship would cause no conflict of interest in IndyCar in 2019, since this is the last year that rival brand Verizon sponsors the series.

Michael Andretti, owner of Andretti Autosport, also attended the Canadian F1 Grand Prix as guest of McLaren.

Brown said: “We’re seriously considering IndyCar, we’ve been doing some due diligence for quite some time.

“As stated before, if we’re going to get into other forms of motorsport which McLaren has a great history in, we need to do it in a way that first and foremost doesn’t compromise our Formula 1 activities, or we wouldn’t consider it.

“It needs to be commercially viable, something we feel we can be competitive in, and fits our brand. It has to tick all of those boxes, not most of those boxes.

“We’re not done yet with our due diligence, but it’s looking favorable. So we’ll take a decision in order to be prepared for 2019 sometime in the upcoming months, and if we’re confident we can tick those boxes, then it’s something we’ll probably move forward on. But we’re not done with the journey yet.”

McLaren built a strong legacy in Indy car racing in the 1970s, both as a works team, and through other teams – notably Penske – running McLaren chassis. Three times the Indy 500 winner was racing a McLaren (Mark Donohue in 1972, Johnny Rutherford in ’74 and ’76), while Roger McCluskey in ’73 and Tom Sneva in ’77 landed the Indy car championship driving McLarens. By the time the brand pulled out of Indy car racing at the end of 1979, it had amassed 28 race victories.

Regarding the possibility of Alonso switching to IndyCar for 2019, Brown said: “We’re in talks with Fernando. It was about this time last year that we started having conversations.

“He’s been doing F1 a long time, I think he’s enjoying driving as much as he ever has. I think he’s driving better than he ever has. He’s a little frustrated with F1 being a bit more of a constructors’ championship than a drivers’ championship. He loves F1, loves WEC [with Toyota], did Daytona [24 Hours with United Autosports] , so hopefully we’ll keep Fernando in the McLaren environment in some way, shape or form.

“I don’t really want to elaborate on the conversations that we’re having with him, beyond what I’ve spoken about. But I think any time he sees a race-winning car in front of him he’s going to want to drive it, no matter what it is. We’ve not got into that level of detail.”

Brown emphasized that despite McLaren’s recent ill-starred partnership with Honda in F1, he would not favor Chevrolet engines over HPD in IndyCar, whether McLaren entered the series as a standalone entity or formed an alliance with an existing team.

“There are two excellent manufacturers, both of whom do an excellent job, in IndyCar,” he said, “and we’d love to race with Honda again. They make great engines, they win a lot of races in IndyCar, so we wouldn’t hesitate to race with Honda if that was ultimately the direction we were headed.

“We’ve spoken with both manufacturers in our process of exploring what we might want to do.”

McLaren spokesperson Tim Bampton told Motorsport.com: “To use an automotive analogy, I think we all feel like [coming back to IndyCar] would put a turbo on the engine in terms of accelerating the awareness of the McLaren brand in the US.

“IndyCar ticks a lot of boxes. North America is a massively important market for us, especially for our road car division, but also important for our partners [sponsors] and important for new prospects.

“We have a lot of activity already in the States for our applied technologies division, in both NASCAR and IndyCar. But as a year-round presence in IndyCar, we would be able to identify the McLaren brand as a frontline racing entity with race fans in the US.”

Bampton, like Brown, did not wish to add to rumors over Alonso’s future, but stated: “If we make the decision to enter, it’s really about long term strategy, so it’s not aligned to any particular driver. There’s a lot of speculation about Fernando, but if we go into IndyCar it’s not just to give Fernando something to do! It’s because we see it as valuable for McLaren’s overall business and brand.”

Bampton also emphasized Brown’s point on the engine manufacturer decision.

“We would consider either of them equally if we ran independently,” he said. “Obviously a partnership with an existing team would push us toward one manufacturer. McLaren and Honda were respectful of each other during the exit from their F1 partnership and we said at the time they are a great company with a huge racing pedigree, so never say never.

“Gil’s relationship with Honda Performance Development [Santa Clarita, CA-based] is also a close one, from his racing as well as consulting. But I still would rate our relationships between the two manufacturers [Honda and Chevrolet] as equal.”

- Additional reporting by Edd Straw