The writer of Gypsy Boy has defended the casting of Benedict Cumberbatch as his father in the film adaptation of his memoirs.

Mikey Walsh’s best-selling autobiography recalls his experiences growing up in the 80s and, realising he was gay, moving away from his Romany community of bare-knuckle fighters.

Cumberbatch has been cast to play Walsh’s father Frank, who placed a pair of golden gloves on a chain around his son's neck when he was born, with the hope that he would continue the family's fighting legacy.

The casting has been criticised for being “tone-deaf”, with many asking why an actor as privileged as Cumberbatch – who was privately educated at Harrow – has been chosen to play someone who is from a disadvantaged ethnic minority.

Walsh has defended the casting on Twitter, writing: “This was My choice. Because No one got my dad the way he did.

“& The real truth is if I cast someone who looked more vile, or like they'd been Smashed in the mouth with a Brick, no one would've blinked an eye. Who's the racist here? This is my family. Be kind x”

When the casting was announced, Cumberbatch said in a statement: “I was immediately drawn to Mikey’s courageous and heart-breaking story. And his father Frank is unlike any character I’ve played before.

“He’s a complex man torn between tradition and his love for a son struggling to come to terms with an identity that’s completely at odds with Frank and his culture.”

It is not yet known who will play Mikey Walsh opposite Cumberbatch in the film.