An unlicensed blood product which claims to treat cancer and autism is still being sold, despite warnings that it could pose a significant risk to health, the BBC has learned.
"GcMAF" is an injectable product made from human blood, produced by Guernsey-based Immuno Biotech Ltd and manufactured in the UK.
The company claims GcMAF is "the body's way of becoming cancer free", that 85% of people with autism "respond", and "15% make full recoveries". It also claims "full recoveries in 70% of cases" of ME and chronic fatigue syndrome.
But experts say there is no evidence to support claims it could potentially cure autism or cancer.
The Medicine and Healthcare products Regulatory Agency (MHRA) has also raised concerns over whether the product is sterile and free from contamination.
Earlier this year, MHRA investigators seized 10,000 vials of GcMAF when they inspected the firm's Cambridgeshire factory. They issued a warning about its sterility and said they had concerns that it might be contaminated.
The regulator advised that GcMAF "may pose a significant risk to people's health" and cautioned anyone who had used it to seek professional medical advice. They said the product had not been not been tested for quality, safety or effectiveness.
Guernsey has its own legislative body, and under Guernsey law it is illegal to market or sell an unlicensed medicine from or within the bailiwick.
Despite this, the BBC has discovered the product has not been removed from sale, with the company offering to supply it to an undercover reporter posing as the parent of an autistic child.
A representative at Immuno Biotech's Guernsey office told the reporter: "Our product is still available, it's just that we can't ship to the UK."
She described how the company, which trades as First Immune, continued to supply customers: "What people in the UK are doing is they give us an alternate shipping address: if it's in Europe, we can ship there."
She advised having the product shipped onwards into the UK and added that the product had "wonderful results" in autistic patients.
First Immune said it would cost 660 euros for one vial of GcMAF, plus 60 euros for a courier service. It said it was regularly shipping the product to countries such as Australia from a dispatch centre in Europe.
Some overseas customers had been paying nearly $1,000 a month for the drug, in the belief it would cure their children of autism.
One mother, who bought the treatment for her son, explained: "You have parents that are desperate and they're trying to help their kids and they'll do anything to help them, and I think they took advantage of that."
She said she feared for her son's health when she read about the MHRA warning: "I thought maybe his blood was poisoned, I was thinking the worst."
The National Autistic Society has told the BBC it is "extremely concerned". Jane Harris, its director of external affairs and social change, said: "There is no serious evidence of any kind to support the claims made for GcMAF.
"We are extremely concerned that vulnerable families, struggling with some of the challenges of autism, could still be supplied with GcMAF, despite the MHRA's warning about this unlicensed product."
Fiona O'Leary runs Autistic Rights Together and has two children with autism. She has raised concerns with both the Guernsey authorities and the MHRA about GcMAF. She said: "Parents can be vulnerable when they receive a diagnosis of autism for their child and many are preyed upon."
The company has also been criticised for its stance on cancer treatment, Its chief executive, David Noakes, advises cancer patients to avoid conventional therapies, saying: "You should not take anything that is destroying your immune system - so we advise strongly don't take chemotherapy because it will destroy your immune system."
Leading cancer charity Cancer Research UK has warned cancer patients not to use the product. Dr Kat Arney, its science communications manager, said: "GcMAF isn't approved or licensed in the UK for treating cancer or any other disease and it may cause harm, especially if people stop conventional treatment in favour of this unproven alternative."
The Guernsey government says it will act on any evidence of unlawful activity relating to the importation, export, manufacture, sale or supply of GcMAF in or from Guernsey. Earlier this year the authorities stopped issuing import licences for GcMAF.
It says its Health and Social Services Department is continuing to work closely with the MHRA in relation to the investigation.
Investigations into GcMAF are also under way outside the UK. Immuno Biotech has supplied the drug to James Jeffrey Bradstreet, a controversial US doctor who used GcMAF to treat patients with autism.
The US Food and Drug Administration searched Dr Bradstreet's premises, with a warrant for GcMAF in July. Three days later Dr Bradstreet was found dead. The local sheriff reported suicide.
Meanwhile, Swiss authorities are investigating a business in Lausanne run by David Noakes, which was treating cancer patients with GcMAF.
The Swiss were alerted after a number of foreign cancer patients who had been visiting the facility in Lausanne were treated at the local university hospital. The patients, who were terminally ill, all died. Two died in Switzerland, the others after they returned home. The premises were not authorised to treat patients and were closed by the authorities.