Sarah Michelle Gellar, star of the cult American show Buffy The Vampire Slayer, which celebrates its 20th anniversary

Buffy The Vampire Slayer creator Joss Whedon has admitted he feels he did not do enough to represent diversity on the show.

Speaking on the cult teen series' 20th anniversary, he said he "missed some of the point" when it came to hiring cast and crew of mixed genders and ethnic backgrounds.

He told The Hollywood Reporter: "I was definitely unaware of how things affected people, how representation was lacking.

"I didn't help out. I didn't make a point of hiring female directors, I didn't make a point of hiring people of colour, I didn't think it through past where I had gotten."

Describing himself as "of a certain era," he added that he "didn't have the bandwidth to care about humans" at the time, passing on that credit to the show's executive producer, Marti Noxon.

But the series, which first aired on March 10 1997 before running for seven seasons, is still hailed as a pioneer in championing a strong female lead, particularly for its target demographic.

The genre-crossing programme followed high school student Buffy Summers, played by Sarah Michelle Gellar, as she tried to balance her life fighting vampires and demons with the more everyday teen troubles of heartbreak and friendships.

Buffy flipped the stereotypical female character in a horror story on its head, putting the protagonist's quest to destroy evil in her home town of Sunnydale as the main story arc.

Whedon said he had wanted to make a "feminist show" that combined a woman taking charge while surrounded by male characters, with the horror genre.

But while he praised the way women are now being given a stronger role in front of the camera, he said equal pay was still a particular problem behind the scenes.

Buffy was the first major television series for Whedon, who went on to work on such box office smashes as Avengers Assemble and Avengers: Age Of Ultron, as well as the TV programme Agents Of S.H.I.E.L.D.

The show was also the launch pad for Gellar, How I Met Your Mother actress Alyson Hannigan, who played Buffy's friend Willow, Bones actor David Boreanaz as Angel and Criminal Minds star Nicholas Brendon as Buffy's best friend Xander.

The series is also notable for starring British actor Anthony Head, who played librarian Rupert Giles, Charisma Carpenter as popular girl Cordelia, Amber Benson as Willow's love interest Tara, and Seth Green as Daniel "Oz" Osbourne.

Buffy spawned a spin-off series, Angel, and Whedon continued the story in comic book form, publishing updates in 2007, 2011, 2014 and 2016.

PA Media