HBO's recent comedy drama Girls, created and co-written by indie wunderkind Lena Dunham, has been the subject of a seemingly endless stream of think pieces. The crux of the matter is the diversity – or lack thereof – that the show displays. A full cast list from Imdb.com showed parts for non-white cast members such as "Jamaican Nanny", "Young Black Guy", "Roosevelt Hotel Bellhop" and "Tibetan Nanny". Of course, Girls is only the latest in a long line of New York-set TV shows that paint a distinctly monochromatic picture. From Seinfeld to Sex and the City to Friends (which recycled the same storyline for two black characters over the series), there is a small-screen tradition of whitewashing the big city.

British TV is not doing much better. The last sitcom with a majority black cast was the Ian Pattison-scripted and almost universally panned The Crouches in 2003. Before that, it was Desmond's, which ended in 1994, but now thankfully lives on on Channel 4oD. The big breakout successes with majority black casts have been in the genre of gritty "urban realism", usually focusing on inner-city London, crime and drug deals. The success of one such programme, Channel 4's Top Boy, has seen it recommissioned for a second series.

British actor and comedian Angie Le Mar recently said: "We decided to make [new sitcom The Ryan Sisters] ourselves and put it up online because we just can't get TV networks interested. There really is a lot of racism in the industry: they're not ready for black women. Commissioners say: 'Can you make white people laugh?' Or: 'Middle England won't like you.'" Her sentiments were echoed by David Harewood, last seen in the US TV drama, Homeland, who said there "aren't that many roles for authoritative, strong, black characters in this country". Whether the fault lies with commissioners or writers, the fact remains that the spectrum of blackness on TV is narrow, and has remained almost stagnant in the last decade or so. Where, therefore, are the newest generation turning in order to see a broader representation of themselves? The internet, of course.

The success of the American series The Mis-Adventures of Awkward Black Girl, which debuted on YouTube in February last year, was unprecedented. Series creator Issa Rae, a 26-year-old Stanford graduate, wrote the title character after reading an article asking "where the Black Liz Lemon [the awkward TV writer played by Tina Fey on 30 Rock] was. And I was like: 'I need to do this now before it's too late,'" she says. Since the show started, its episodes have been viewed more than 6m times and it has more than 61,000 fans on Facebook. When the producers ran out of money mid-season, they started a fundraising drive – contributions from fans came flooding in, eventually raising more than $56,000. The ABG (as it's known to its fans) brand has even spread to retail – you can buy t-shirts, wristbands and decals from their online shop.

The success of ABG has opened the floodgates for minority film-makers. Web series such as The Number, The Couple, and The Unwritten Rules have popped up in the last year; written, produced and starring black and non-white actors in roles less restrictive than mainstream TV often allows. With a host of new black dramas, the British are catching up too.

Brothers With No Game

The Brothers With No Game is a blog written anonymously by four twenty-something friends from London. It follows four men as they traverse London life, relationships and jobs. Their web series debuted on 11 June. For them, writing the show as a web series was an obvious choice. "We started with the blog in October 2010 and have had an amazing response; more than half a million hits. We began thinking it would work well as a series and decided on an online sitcom. With an online medium, we can do things our own way," says Justin Credible (one of the creators' nicknames).

The "Brothers" are in their mid-20s (25 to 27) and are all of British African descent. They all came from non-TV backgrounds: how much of a challenge was that? "From a writing perspective, it wasn't anything too new, although it's a scripted format. One of us is hoping to become a scriptwriter, so this is kind of their niche," he says. "We've been fortunate enough to have a producer who had produced a couple of online things, and he gave us the benefit of his experience. But we don't have a huge production company behind us." Funding the show has also proved challenging: "We have to fund everything ourselves – we've had to be creative with what we have in order to make it work. But people have seen what we're trying to do and have asked to join in." They've read the blog and enjoyed it and they want to be a part of it." BWNG are planning a Crowdfunder campaign (the UK equivalent of Kickstarter) in the future, from which they will pay the actors and production costs.

A casting call brought in 80 actors, something Credible describes as "an amazing response. It was obviously something that they thought would do well, and it shows how people want to get into meatier roles that are a bit different." On the subject of blackness on television, Credible says: "I don't think we're given a chance to really showcase what we're all about in terms of the black British population. I mean, Top Boy and My Murder are brilliant TV and really engaging viewers but I think there's also space for dramas and sitcoms and thrillers." He continues: "Variety is the key message here. There's a narrow representation of what it means to be black; there need to be different stories told." The rise in web series by black creators is a direct response, he says. "It's why we're taking things into our own hands. If it's not going to be on TV, at least we'll be online - it'll be interesting to see how it impacts television."

Venus vs Mars

Baby Isako's dream was to write her sitcom, Venus vs Mars, for TV. But, she tells me, it's no easy thing: "To get a whole black cast put on TV is really hard work, a long process," she says. "I felt it was something that needed to be done now, straight away. The urban audience in the UK market is really growing, so I thought: 'Let's do the series, make TV come to us and not the other way round.'" For Isako, 24, the web was attractive for other reasons – an instant worldwide audience. "We get people watching it from America, Europe, everywhere. It just shows how powerful the web actually is." The success of ABG has spurred her on. "I feel like we in the UK look up to the Americans and how they do things," she says. "Hearing that shows like that can actually be successful; you get inspired to take the risk yourself." One of the risks she's taking is the funding of the show: "I'm lucky enough to have an up-and-coming production company, Purple Geko, who came on board as part of Talented and Young," she says. "They've got all of their equipment and they do all the editing and the additional costs are funded by them." The show features actors she's previously worked with in theatre, but they also held an open casting call. "Some people are naturally gifted," Isako acknowledges.

The show will have an initial run of six episodes, to give it a chance to bed in and gauge the response. "We'll see if there are any channels interested in picking it up, or if there's funding that we can get to continue being an online series," she says. Ultimately, though, Isako wants mainstream success: "I would like it to go to national television. But if that doesn't happen, then we're happy with it being online."

She describes the series as a "light-hearted romantic comedy"; the star of the show, Venus, takes us on her quest through the dating wastelands to find Mr Perfect. It's a genre she feels is not seen as the natural home for actors of colour: "I don't like the representations of 'blackness' on British TV. For me, as a young black female, I cannot turn on the TV and find a character I can relate to, that I can identify with," she says. "Every time, they're the girlfriend, the drug-related/gang/estate role. I'm not surrounded by people like that so I can't watch those shows and relate. That's why I became a writer, to write different roles. We want to show that there's an audience for this type of series, it's different to what's on TV." Series such as Isako's will help to combat this mentality. "I think we need a lot more black and minority ethnic writers coming up and taking risks. If you want something to be changed you have to work. Who's writing these shows? Top Boy was written by a white writer! There's a stereotypical idea – 'this is what black people are like' – and it's not true."

All About The McKenzies

For Samuell Benta, 25, getting All About The McKenzies up and running has taken two years. He originally conceived the idea as a traditional TV sitcom. "Flicking through channels, I was just seeing American stuff. In the US, there's an abundance of black shows, but in the UK, we've got little to nothing – and in what we do have, we're negatively represented." He did his research, he says. "Desmond's, The Real McCoy, all of that. I saw the most recent was The Crouches and thought, "why didn't that work?" and went from there. There's a difference between the US and Britain - it's not the talent; it's the creative idea behind it, the direction. I think over here they water our stories down, just to suit what they think the audience wants."

He filmed a speculative 22-minute pilot for TV last April, but the footage was unusable: "The camera angles were awful, the cameraman hadn't filmed everything he was supposed to," says Benta. For seven-and-a-half months, Benta floundered. But attending the Hollywood black film festival in Los Angeles, "I discovered the web stuff going on out there. I thought, 'if there's a way this can be done for free, why am I asking around for all this money?'"

By January this year, he had rewritten it for the web and filmed it over five days in February. The series is about three generations of a family, the McKenzies – complete with a wisecracking grandad, a CID detective father and a teenage boy obsessed with being cool. It also stars Benta, who plays a version of himself – a single dad who wants to spend more time with his daughter. In April, he attended a web festival in America where the series won an award for best ensemble cast in a comedy – the sole British winner. Benta is not new to the camera – he has played a part in EastEnders: E20 and a generation of kids will remember him as Will Aston, the Black Ranger in Power Rangers Operation Overdrive.

"I wasn't supposed to be the director, or the only writer, and I was looking for a producer, but circumstances meant I had to take on the whole project myself," he says. The first season of eight five-minute episodes was financed by him alone. "All the actors did it for free. And so did the cameraman, editor, and the graphics people. I have a good relationship with the head teacher of the school in the show, which allowed me to use the school for one day and the students were extras. Making the series allowed him to make use of newly acquired skills. "I run a service where I write and direct actors' demo reels, so I learned to direct from that. But I also learned by being on set and watching directors – I used to shadow directors on Eastenders. And luckily, all that happened within the period of my stuff getting stolen so I built up that experience."

Benta has had interest from a couple of entertainment companies and is weighing options. "There's interest now – people want meetings – so clearly I've got something. But I'm a first-time producer, and it's got to the stage where I need to educate myself on the business side of things." What does the future hold for the McKenzies? Benta is happy – for now. "The original idea was not for the web. My intention is still for it to be a TV series."