For three days at the end of January, the Renaissance hotel in Washington DC fills up with television executives from around the world. The Realscreen Summit is where the makers of reality TV gather to discuss ideas, negotiate deals and discover the next Apprentice or I'm A Celebrity. Among the estimated 2,200 people who had paid up to $1,600 (£1,050) this year to try to snag face time with an exec from Freemantle, TLC, Discovery or National Geographic was an Englishman in his mid-50s wearing jeans, a crisp, white shirt and loafers, and carrying a MacBook. On his badge were the words "Autism Team".

This man's pitch was a reality TV series about autism, and he had a short trailer on his laptop: an autistic child screams; another bites his mother's hand; another repeatedly and violently slams a book against his head. Then a narrator tells us that "every day across the world, medical symptoms of hundreds of thousands of people with autism are being ignored". Cue piano music and the titles, The Autism Team: Changing Lives.

The premise is that the autism symptoms suffered by the children in the promo (Jon, 14, who is "wasting away"; six-year-old twins "still not potty trained"; and 15-year-old Jack, who is "non-verbal and very self-injurious") have left their parents feeling helpless and alone — until, that is, the Autism Team steps in to save the day.

One member of that team is Arthur Krigsman, a paediatric gastroenterologist who, we are told while we view images of Jon unconscious in a hospital bed, breathing apparatus attached to his mouth, is investigating the little boy's intestinal symptoms. "He has the autism-associated enterocolitis," Krigsman says. "That's exactly what he's got." He adds: "It's all treatable." Jon's mother says Krigsman's diagnosis is the answer to everything. Jon's father tells us the subsequent change in his son has been "absolutely dramatic". Finally, as the short teaser wraps, the narrator says that "groundbreaking work by the Autism Team means that children can be treated effectively. So join us and follow their journey."

The man in the white shirt and jeans punting the prospective TV series that day was Andrew Wakefield, coauthor of a now notorious 1998 study, published in the Lancet, that suggested a possible link between autism, gastrointestinal disease (it was Wakefield who coined the term "autistic enterocolitis", which Krigsman diagnoses in the Autism Team trailer), and the measles, mumps and rubella (MMR) vaccine. Afterwards, Wakefield called for the suspension of the triple jab, which caused widespread panic and is said by his critics to have resulted in a drop in the number of parents choosing to vaccinate their children. Cases of measles rose from 56 in 1998 to nearly 1,400 in 2008. In 2006, a 13-year-old boy became the first person in more than a decade to die of the disease in Britain.

An investigation by journalist Brian Deer found that Wakefield had been paid £435,000 to advise lawyers for parents who believed their children had been harmed by MMR and that he'd given children at his son's birthday party cash in return for blood samples for his research. A subsequent two-and-a-half-year General Medical Council (GMC) hearing concluded in January 2010 that Wakefield was guilty of serious professional misconduct, and that he had acted "dishonestly and irresponsibly" in his research. He had, the panel concluded, subjected 11 children to unwarranted invasive tests such as lumbar punctures and colonoscopies without necessary ethical approval. The Guardian reported at the time that the GMC hearings also found that, before the paper was published, Wakefield had filed a patent as the inventor of a vaccine to eliminate measles and treat inflammatory bowel disease. In May 2010, the GMC struck him off and the Lancet eventually retracted the 1998 paper.

In 2001, Wakefield, his wife, Carmel, and their four children packed their bags and moved to Texas, to a house in the hills west of Austin. There he founded Thoughtful House Center for Children to further his work on autism and served as its executive director on a salary of £164,000, before resigning in February 2010 following the GMC ruling. Krigsman also worked at Thoughtful House, as director of the gastroenterology clinic, and left soon after Wakefield.

Wakefield then set up the nonprofit Strategic Autism Initiative to commission studies into the condition, and is currently listed as a director of a company called Medical Interventions for Autism and another called the Autism Media Channel, which produced the TV trailer.

Since that notorious Lancet paper, numerous studies on MMR and autism have failed to find a link. One of those studies, which reviewed the medical records of 500 autistic children born in a specific area of London since 1979, found no difference in MMR vaccination rates between children with autism and those of the general population, and no evidence that children vaccinated with MMR at younger ages developed autism any earlier than children vaccinated later.

Another, published in 2008, found "strong evidence against association of autism with... MMR exposure". According to the US National Institutes of Health, evidence from the UK against an MMR-autism link has been accepted by the American Medical Association, the American Academy of Pediatrics and the Centers for Disease Control and Prevention.

In his book Callous Disregard, Wakefield claims his findings of autistic enterocolitis have been "independently confirmed in five different countries". He cites five studies, two of which were authored by his friend, collaborator and Autism Team star Arthur Krigsman. One of those studies appeared in Autism Insights, a medical journal on whose board Krigsman sat in 2010. Two other studies were by Italian doctor Federico Balzola. According to the justthevax blog, the first of these was a case report of a single adult autistic patient with an inflamed bowel, and the second a "meeting abstract" that "never saw the light of day as a peer-reviewed study". The last one, a study by Dr Lenny Gonzalez, while not reporting finding a distinct "autistic enterocolitis", concludes that "autistic children have a high incidence of gastrointestinal disease".

In May 2010, just a few days after he was struck off by the GMC, I interviewed Wakefield in Chicago for another story. For someone so vilified in his own country, he was remarkably self-assured. He was there to promote his book, which he describes in the prologue as "a story of how the system deals with dissent among its doctors and scientists". Although soft-spoken and polite, he had harsh words for the British medical establishment, which he felt had suppressed his work. In 2011 he issued a statement saying he continued to support independent research "to determine if environmental triggers, including vaccines, are causing autism and other developmental problems".

Then, in January 2011, Brian Deer, writing in the British Medical Journal (BMJ), accused Wakefield of outright fraud, saying he had altered the medical histories of his patients to support his claims and that he sought to exploit the MMR scare for financial gain.

Wakefield maintains that the BMJ and Deer are pursuing a vendetta against him, and says these allegations are false. He sued the magazine, its editor Fiona Godlee and Deer in Texas, and although his case was initially struck out on technical grounds, he is appealing and continues to maintain that the scientific research he conducted was not fraudulent.

In January, Wakefield told a media outlet in Austin that there has been a "relentless assault on the few – perhaps five, 10 – scientists in the world who are prepared to work on the possible association between vaccines and childhood developmental disorders like autism".

The fact that science hasn't furnished us with answers as to what exactly causes autism, and that we still don't have a cure (although the concept of finding a "cure" for autism is in itself controversial), has meant treating someone on the spectrum has become an area of considerable contention among some doctors and parents, and created a landscape ripe for people peddling all kinds of therapies, supplements and biomedical interventions, many of which are not supported by peer-reviewed scientific studies.

The UK's Wellcome Trust Centre for Human Genetics, a research institute of the University of Oxford, estimates that "genetic factors may contribute about 90% to autism, while environmental factors contribute no more than 10%". Similarly, according to the American Medical Association, "autism is strongly genetically determined".

But some people, Wakefield included, insist that the cause of autism is largely environmental. "You do not have a genetic epidemic," Wakefield told Wisconsin's Lakeland Times last year. "The cause is environmental." And this view – that environmental toxins cause autism – directly impacts what treatments proponents of the hypothesis recommend.

The Autism Media Channel website contains videos with titles such as Not Born With It – a reference to the belief that autism is far from genetic, which leads it to advocate biomedical interventions such as nutritional supplements as well as gluten- and casein-free diets (one video is entitled How To Afford A Gluten And Casein Free Diet). Other videos recommend that parents of autistic children cook food using stainless-steel or ceramic pots so metals don't "leach into the food and give more toxic overload to your kid".

Dr Michael Fitzpatrick and his son James: ‘You just have to play with them and love them as best you can.’ Photograph: Kate Eshelby

In his book MMR And Autism: What Parents Need To Know, Michael Fitzpatrick says that a 1996 review of methods of assessment and intervention for young children with autism conducted by the New York State department of health concluded that "special diets, including elimination diets, are not recommended as treatment for autism in young children". The report noted, Fitzpatrick wrote, that there were "no known advantages to special elimination diets for children with autism, and expressed concern that they may cause the child to get inadequate nutrition…"

The presenter of many of the Autism Media Channel videos is Polly Tommey, who is also registered with the Texas secretary of state as a co-director of the company, along with Wakefield. Tommey, who recently moved to Austin from the UK with her husband, Jonathan, and their three children, first appeared on the autism radar in 1999 when she and Jonathan were guests on Tonight With Trevor McDonald. That evening they announced that they had given their autistic son, Billy, an infusion of the hormone secretin, extracted from pig intestines, which stimulates digestive fluids in the pancreas, produces pepsin in the stomach and bile in the liver and, they said, resulted in "excellent progress".

In his book on autism, Fitzpatrick writes that secretin was "enthusiastically endorsed by some prominent figures in the world of alternative autism" but, by December 1999, "the secretin bubble burst" when a double-blind placebo-controlled trial of 60 autistic children concluded it was not an effective treatment. Four later trials echoed the conclusion, according to Fitzpatrick. Then, a 2004 review of 15 double-blind, randomised, controlled trials of secretin for autism showed almost none reported any significant effects and none concluded that secretin was effective.

In 1999, Tommey started The Autism File, a slick magazine and website designed to showcase "anything relevant to autism". One story suggested, "We, as parents and physicians, need to implement strategies to reduce our children's chemical and heavy metal toxicity levels", and advocated the highly controversial procedure known as chelation therapy, whereby heavy metals are removed from the body using "chelating" agents — the presumption being that autism is caused by mercury in vaccines or that people with autism spectrum disorders find it harder to filter "environmental toxins".

Chelation is the introduction of chemicals (and there are several, including dimercaprol, which was used during the second world war as an antidote to the chemical warfare agent Lewisite), either orally or intravenously, which then bind to poisonous metals such as mercury, arsenic and lead so they can be excreted.

Although it has approval for treating people with heavy metal poisoning, it can be dangerous and is not approved for use in treating autism. In 2005, a British boy, Abubakar Tariq Nadama, died of a heart attack while undergoing chelation in America. Last spring, a doctor in Hertfordshire was given an official warning by a Fitness to Practise Panel after she used chelation on an autistic child without measuring his blood lead concentration or referring him to a toxicology specialist. What's more, an analysis in the US of five chelation studies showed that none provided any certainty that any benefits shown in the children were due to chelation itself, "and not another treatment or just kids getting older".

According to Mike Stanton, British author of Learning To Live With High Functioning Autism and the father of a son with Asperger's syndrome, the Tommeys are now "linked to these people in America who think diseases are better than vaccines – that diseases will give you immunity and vaccines will kill you. [Tommey] knows Wakefield is a busted flush over here. That's why they've gone over there."

In 2007, Tommey started the Autism Trust to "raise awareness" and fund the building of a residential centre for adults with autism. Wakefield's wife, Carmel, sits on the board of directors; Imogen, the Wakefields' daughter, is listed as a member of the "junior advisory board".

Three years later, Tommey launched a campaign aimed at getting David Cameron, Gordon Brown and Nick Clegg to put autism in their general election manifestos. To get their attention, she appeared on billboards wearing a bra. "Hello boys," the poster read. "Autism is worth over six million votes. It's time to talk…" In her campaign video, she even brought up the "safety of our vaccinations", claiming the issue "wouldn't go away". It proved polarising thanks to Tommey's support for Wakefield and her call for residential centres for people with autism when other charities believed care should be brought into the wider community.

In 2012, Tommey's then-16-year-old daughter Bella launched a charity campaign called Give Autism A Chance. Its aim was to demonstrate that people with autism could contribute to society. In London, Bella set up Billy's Cafe, named after her brother, in which autistic people could work. The aims of Give Autism A Chance were noble, but proceeds would, Bella said at the time, be given to her mother's charity, the Autism Trust. Later the same year, Bella took the campaign to Texas with the help of Wakefield's daughter, Imogen, and they launched it at a cafe in Austin.

Meanwhile, Jonathan, Tommey's husband, who has a sports science degree and a foundation degree in nutritional therapy, set up the Autism Clinic in Berkshire to offer "specialist autism treatment", including "diagnostic tests" and an array of supplements and vitamins that he prescribes and makes available from his online shop. He also features in some of the programmes on the Autism Media Channel's YouTube page. In one of those films, Jonathan Tommey – The Biomedical Imbalances In Autism, he recommends "supplementary intervention" such as "vitamins and herbs" for children with autism. In the same film he discusses chelation therapy. "As nutritionists, we can't use chelating agents. They are prescriptive medications," he says, adding, "They are available on the web. My suggestion is you've got to be very careful doing this without professional guidance, and unfortunately in this country there are not many practitioners that do chelation." But, he adds, "Chelation has been used to a good level of success."

According to his website, an initial consultation at the Berkshire clinic is £300. Follow-up consultations "and communications" are £90 an hour. In his online shop, Antioxidant Complex costs £34.70; Immunoguard, £24.15; Kids Complete Complex, £12.95 – and something he calls Mood Food is £24.45.

The Autism Science Foundation, which helps fund autism research, warns against what it regards as non-evidence-based treatments that haven't undergone rigorous, well-designed scientific studies. Gluten-free, casein-free (GFCF) diets, it says, are promoted by those who "claim that children with autism have 'leaky guts' [a theory Wakefield espouses] that allow opioids to escape into the bloodstream and then travel to the brain and cause autistic behaviours". But, according to the foundation, there is no evidence for the claim, "and studies have found that compared to typically developing children, children with autism have no more opioids in their blood. Furthermore, children on the GFCF diet have been found to have lower bone density than controls, which could lead to osteoporosis." As for vitamins, it says doctors may recommend nutritional supplements to people "with and without autism" as part of a "healthy and balanced diet", but it says, "Use of supplements can be problematic… when they are misused in an attempt to cure an individual of autism. There is no scientific evidence suggesting that vitamin supplements can cure autism [and] some supplements (such as vitamin A) can be toxic when taken in high doses for sustained periods." An investigation into alternative therapies for autism by the Chicago Tribune in 2009 found many had "little basis in science" and amounted to "uncontrolled experimentation on children".

The Autism Media Channel's YouTube page also features numerous interview clips of Wakefield defending himself against the allegations that emerged during the GMC hearings and later in the BMJ. Looking relaxed in a pink shirt and sitting in front of a bookcase, he is asked questions such as: "What exactly were your findings with regards to the MMR vaccine and autism?" His response to that question: "In the Lancet study, the report that we provided was what the parents told to us. And that, for eight of the 12 children, was that after a period of normal or near-normal development, their child had a vaccine and shortly after that, regressed into autism."

Polly Tommey believes giving her son Billy the hormone secretin, from pig intestines, has resulted in 'excellent progress'

There is a considerable body of opposition to the approaches advocated in many of the films on Wakefield and Tommey's Autism Media Channel. Steve Silberman, a contributing editor to Wired magazine in the US and author of an upcoming book on autism, NeuroTribes: Thinking Smarter About People Who Think Differently, doesn't pull his punches. He calls the images of autistic children undergoing violent outbursts at the start of the trailer a "horrifying freak show [which] demeans people on the spectrum of all ages". He believes that Wakefield should be advocating investment in desperately needed lifelong support and services. "The last thing autistic people and their families need is more stigmatising stereotypes – which encourage bullying and despair."

Martine O'Callaghan, who runs the Autismum blog from her home in Wales, is the mother of an autistic son, Cledwyn, who is four and a half. "From the point of view of another mum with an autistic child, I don't like Polly Tommey's idea that autism is something to cure," she says. "The idea that autism is something to be fixed is dehumanising. It deeply offends me."

Kassiane Sibley agrees. She is autistic and describes herself as an activist and advocate for autistic people. She finds Wakefield's concept for a reality TV show appalling. "Their whole paradigm for autism is really insulting to us… How would you like it if somebody portrayed all British people as violent, tortured souls who could be Americanised into calm, non-violent 'real' people?"

Sibley profoundly disagrees with Wakefield's approach. She feels the Autism Team are "completely divorced from scientific reality". In her view, they are using the media to push what she regards as a "completely false view", and she worries that's "going to hurt a lot of people… There have been many studies showing that these biomedical treatments don't help."

As a child, Sibley says, she was given vitamin B6 in an attempt to cure her autism. "Take too much and you get neuropathy," she tells me. "That's a fun one, and by fun I mean not fun at all, because you can't feel your toes and your fingers, and they burn, and then you're yelled at for walking on your toes when you're just desperately trying to get the feeling back. If you read anything about alternative medicine, you'll know much of it works on the placebo effect."

Ari Ne'eman, who in 2009 became the first person with an autistic spectrum disorder to sit on the US National Council on Disability (he was appointed by Barack Obama), calls the autism trailer "unquestionably offensive". He says it's a "very old trope in the autism world, and it really presumes the only way that we as autistic people can have value is if somebody swoops in to try to save us.

"The idea," he says, of "the poor, pitiful disabled person that we need to save, because Lord knows they're not worth anything otherwise, belongs on the ash heap of history."

Ne'eman says Wakefield and Tommey's message doesn't address the practical services or support that he insists the autistic community – in both the UK and US – needs. As for accusations that people such as Ne'eman don't want to focus on research into the actual causes of autism or "cures", he laughs. "In America we've spent over a billion dollars on autism research. What have we got for that? We've not seen anything that's appreciably impacted the quality of life of autistic people, regardless of their place on the spectrum. Quite frankly, we've spent $1bn figuring out how to make mice autistic and we'll spend another $1bn figuring out how to make them not autistic. And that's not what the average person wakes up in the morning aspiring to. They think: am I going to be able to find a job, to communicate, to live independently, either on my own or with support? Those are the real priorities."

Despite the opposition, Polly Tommey and Andrew Wakefield seem determined to see the Autism Team TV series reach beyond their current niche on Information TV channels. Speaking to the Age Of Autism blog, Tommey said, "The TV networks in the US need numbers, and we have to prove that autism is an issue that people are interested in so they'll be willing to broadcast this series."

Neither the Tommeys nor Wakefield would speak to me for this story. Instead, I sent a list of questions to them via email, and Polly Tommey and Wakefield responded through their US lawyers. In a 10-page letter, their attorney insisted that the scientific research conducted by Wakefield was not fraudulent. Referring to the treatment of autistic children portrayed in the Autism Team trailer specifically, it said, "Extensive references to observational and controlled clinical studies confirm the excess risk of gastrointestinal symptoms in children with autism… confirm the presence of functional and pathological changes in the intestine of children with autism, and… document the benefits of dietary exclusion, particularly using a gluten- and casein-free diet in children with autism." It said the treatments depicted on the Autism Media Channel and in the Autism Team trailer were not used to treat autism, but to "treat gastrointestinal disease and related pain in some autistic patients. My clients have not claimed that they or anyone else can 'cure autism'. What they do suggest is that some symptoms suffered by some children with autism can be treated and the lives of those children can be improved."

The letter went on to say the Autism Clinic (run by Jonathan Tommey) "is not part of or affiliated with the Autism Media Channel". It said, "An extensive review of the relevant medical and scientific literature based upon over 150 published research studies has been provided by Dr [James] Adams and is essential reading for anyone seeking to comment on the merits of nutritional and dietary interventions in autism."

It's worth pointing out here that Adams, whose work they recommend, is a doctor in materials engineering. He also directs the autism/Asperger's research programme at Arizona State University, was the lead author of the 2005 report on Treating Mercury Toxicity In Children With Autism, and also advocates GFCF diets, vitamin supplementation and chelation therapy. "There is substantial evidence to suggest that many children with autism suffer from exposure to mercury, and probably other toxic metals and toxic chemicals," he wrote in a 2007 Summary Of Biomedical Treatments For Autism.

Michael Fitzpatrick, author of MMR And Autism: What Parents Need To Know and Defeating Autism: A Damaging Delusion, is a recently retired London GP. He and his wife, Mary, are the parents of an autistic son, James. Fitzpatrick tells me the key problem, still, for parents of autistic children is that doctors will say they don't know what causes it and that there's nothing you can do about it – two things that are difficult to live with. He describes the impotence he felt watching James regress at 18 months, after he had been developing normally. For parents witnessing that happen to their child, the need to "do something" can be overwhelming, he says. "And then someone else comes along and says your doctor's useless, that they know what caused it, and that you can do something about it."

He says one reason special diets are so popular, despite being unproven, is that they give parents something to do on a daily basis. Luckily, it's the same with behaviour therapy, which has been proven to benefit some children. "You just have to play with them and love them as best you can," Fitzpatrick says. "James's behaviour was very demanding. He'd injure himself, and if you tried to stop him, he'd be very aggressive, but we finally got him into a school that could really manage him and he thrived. He went from being very withdrawn to being happy in himself and much more socially engaged."

James, now 20, has never spoken, and he won't be able to work, but Fitzpatrick says he has seen a change in his son that's very gratifying. He has just moved into an assisted-living home with two boys from school. "And it's working," Fitzpatrick says. "He is a lovely boy. He's great fun."

As for chelation, hyperbaric oxygen chambers, or even more innocuous treatments such as dietary supplements, Fitzpatrick calls them a "colossal waste of parental energy and a distraction. We need to find out what really does cause it, but most importantly what works in terms of helping people with it. That's where we need to concentrate our energies. It's better than chasing phantoms."

And what of Wakefield? In the UK at least he appears something of a phantom himself: in a phone call to the National Autistic Society, asking for a comment for this story, the press officer said, "I'm sorry – who's Andrew Wakefield?" And unless his TV series is snapped up by a broadcaster over here, perhaps that's the way it'll stay.