As part of his quest to win the triple crown of motorsport, Alonso has agreed a deal with Toyota to race in the Le Mans 24 Hours and other WEC events alongside his programme with McLaren in F1.

Speaking to media at McLaren's Woking factory, Brown stressed that Alonso was loaned to Toyota and that the Spaniard should be thought of as "a McLaren F1 driver first and foremost".

"Fernando is effectively restricted to just driving the [Toyota] race car," Brown explained. "So as far as commercial appearances, sponsor commitments, things of that nature, it is very minimised.

"His relationship with Toyota - he is on loan from us. We came to an arrangement with Toyota and that is to allow him to race the car but not to travel the globe having commercial commitments.

"[It's] everything from minimising his travel, to any potential sponsor conflicts – Toyota don't have many on there so there aren't many sitting there today that are a conflict with McLaren.

"But if they do find a partner that is conflicting with McLaren, we couldn't have Fernando walking around in competing sponsor attire.

"Also, he is a McLaren driver first and foremost, and an F1 driver. When you think of Fernando, you think of him as a McLaren F1 driver first and foremost."

No risk of burnout

Alonso was originally slated to do four WEC events this year, but will now run in all five scheduled for 2018 – after the Toyota-owned Fuji circuit successfully lobbied to bring its WEC race forward and avoid an F1 clash.

Asked whether the Spaniard's Toyota programme had any downsides for McLaren, Brown said: "No. Not at all.

"I think, what he will be doing on those weekends otherwise? He wouldn't be testing in an F1 car, he wouldn't be here on a simulator. There is only so much he can do.

"We have got everything we need on the F1 front, so the weekend he would either be in a a go-kart or golfing or whatever he wants to do, he will instead be in a Toyota WEC car. He wants to spend his spare time in race cars."

Mark Webber, who competed in WEC's LMP1 class for three seasons after leaving F1, said he was worried Alonso's grand prix results could suffer if the Spaniard ended up "burning too many candles" with his Toyota effort.

Brown, however, is not concerned Alonso could get burned out from the demands of a dual programme.

"He knows what he is getting into. He is unbelievably prepared. He went from the 24 Hours of Daytona and then got in a simulator test with Toyota for however long he was in the car.

"I think he is a very special athlete who can do things that most of us [here] would get knackered doing. I don't think he would do it if he didn't think he could do it at the highest level."