McLaren is said to be considering a two-car IndyCar team for next season, having held discussions with engine manufacturers Honda and Chevrolet.

Carlin joined the IndyCar series for 2018 despite missing its self-imposed deadline of September by a month, requiring it to play catch-up in the first half of the season before becoming an increasingly regular points-scoring team. Team boss Carlin says his experience suggests McLaren will find a 2019 start difficult to achieve.

“If a team like McLaren wanted to set up a whole new team, they should be well underway doing it with four or five cars, trucks, equipment and trying to get staff,” Carlin told Motorsport.com.

“I can only speak from our experience, but we had the go-ahead at the end of October [2017] and it coincided with a new car package, which meant Dallara was stretched, so we didn’t get our first car until after Christmas and testing started a week or two later. It might be easier for new teams this year, but it's still tough.”

Carlin says that McLaren’s finances will help make up time, but that recruitment will be the biggest stumbling block.

“It depends if they can get decent people and how quickly they get them,” he said. “Most decent people are working so you won't get them until the end of the [IndyCar] season in September.

“Obviously, huge budgets play a part and you can get moving quite quickly, but, at the end of the day, it's about getting the right people, not just spending cash. A team with money like McLaren will find buying cars and equipment easier, but staff is another level.

“A partnership [like the McLaren-Andretti entry at the 2017 Indianapolis 500] is just putting a car in an existing team, that's basically sponsorship and much easier. But McLaren seems to want to do their own team, so they should be on the job themselves.”

Three-time Indianapolis 500 winner Johnny Rutherford, who scored his first two wins with McLaren’s works team, was at the McLaren Technology Center this week to pose with the Borg-Warner Trophy and his newly restored 1974 Indy-winning McLaren M16C.

He appeared to concur with Carlin’s assessment that McLaren has left it too late to re-enter IndyCar fulltime in 2019.

Rutherford, who was the ambassador for McLaren’s 2017 Indy 500 bid with Fernando Alonso, told Motorsport.com: “Honestly I think they’re too late for doing it for next year. I think they need to start now for 2020.

“I don’t know exactly what’s going to happen with McLaren. There have been some rumors and some talk about them coming back, but there’s no way to know."

Rutherford said a full-season program would require significantly more work than another one-off Indy 500 run.

"It’s a lot different, it's a time-consuming effort and they need to do some testing, they need to hire somebody that knows the circuits and put them on the right track," he said.

"There’s a lot of questions that need to be answered."