Director Jon Favreau poses for photographers upon arrival at the 'Lion King' European premiere in central London, Sunday, July 14, 2019. Picture: AP

Jon Favreau says that directors such as Martin Scorsese and Francis Ford Coppola are entitled to criticise the Marvel Cinematic Universe if that's what they believe.

Favreau has both acted and directed in the Marvel Cinematic Universe, helming the first two "Iron Man" movies, and he insists he is unmoved by the pair's criticism of the superhero genre and he still considers them to be inspirations for his own work.

In an interview with CNBC, the 53-year-old filmmaker said: "These two guys are my heroes and they've earned the right to express their opinions. I wouldn't be doing what I'm doing if they didn't carve the way. They've served as a source of inspiration, you can go all the way back to 'Swingers' where I was referencing Marty, and I've worked with him. For me, they can express whatever opinion they'd like."

"The Irishman" director Scorsese, 76, sparked a debate about the value of the MCU earlier this month after comparing the experience of watching one of the blockbusters as being akin to visiting "theme park".

Numerous Hollywood figures have weighed in with their view, whilst MCU alumni such as Samuel L. Jackson, James Gunn and Taika Waititi defended the franchise, but 'The Godfather' director Coppola went even further in his criticism, branding Marvel movies as "despicable".

Speaking at the Lumiere Festival in France, 80-year-old Coppola said: "When Martin Scorsese says that the Marvel pictures are not cinema, he's right because we expect to learn something from cinema, we expect to gain something, some enlightenment, some knowledge, some inspiration. I don't know anyone that gets anything out of seeing the same movie over and over again.

"Martin was kind when he said it's not cinema. He didn't say it's despicable, which is what I say."

Veteran British director Ken - whose films include 'Kes' and 'I, Daniel Blake' - has also slammed the MCU insists the movies are "boring" and are like the fast food of cinema.

Loach, 83, said: "They're made as commodities like hamburgers, and it's not about communicating and it's not about sharing our imagination. It's about making a commodity which will make a profit for a big corporation - they're a cynical exercise."