Thalidomide, one of the most notorious drugs in recent history, is 50 years old this year. The drug was withdrawn in Britain in 1961, but its legacy lives on in the form of the 455 people born as Thalidomide babies. All are now in their forties. But in Brazil, long after the drug's effects were understood, a new generation of Thalidomide babies was born, and may still be being born even today.

Actor and presenter Mat Fraser, himself a Thalidomider, looks at the controversial history of the drug, and travels to Brazil to learn why it is still being prescribed to this day. He meets some of those whose lives have been most affected by the drug, and learns to see Thalidomide from a completely new, surprising angle.

It's a powerful, emotional and often infuriating journey for Mat as he encounters everything from compassion to indifference to greed in his search for answers about the drug that, astonishingly, may be about to make a remarkable comeback to the medical counters in Britain.

When it first hit the markets in 1954, the German-made drug Thalidomide was hailed as a non-toxic wonder-drug, used to treat everything from colds to insomnia to morning sickness. Mat's mother recalls giving birth in January 1962. "After he was born, there was a very heavy silence... And I thought 'Oh, he's dead'." The subsequent discovery that he had short arms proved to be an overwhelming relief, and she talks candidly and matter-of-factly about raising a Thalidomide son. Mat recognises that, with a loving mother, in an affluent society, he has been luckier than many. What has happened to the new generation of Thalidomiders born in Brazil? How do they cope, particularly those embroiled in poverty?

Mat's first impression of Brazil is that people are more accepting of his disability. "What really fazes them is when I tell them I'm a vegetarian." This refreshing, tolerant approach that has helped two young Thalidomiders Mat meets, Hercules and Bia, to come to terms with their condition. Both are happy and unselfconscious and are sexually active young adults. Mat regrets his own awkwardness at their age.

In Brazil, Thalidomide is prescribed to treat leprosy. Mat visits Milena, a young woman who takes the drug to alleviate her terrible pain. It is the first time he has ever seen the drug, or packaging, itself. It is a revelatory moment. "When we're faced with this level of need, I can't see how anyone can begrudge taking it. It's become something else to me already. It's become not just the pill that made me like this. It's the pill that stops her being in abject misery and pain."

Mat sees with his own eyes the desperate need for Thalidomide. The government insists that carefully monitored treatment programmes ensure that those receiving the drug do not become pregnant. But the President of the Brazilian Thalidomide Society believes otherwise. She takes Mat to visit an impoverished family living in the interior, whose daughter exhibits the birth defects associated with the condition. But there is no proof that one of the drugs the mother took to treat her leprosy was Thalidomide, and the devastated family are left without compensation.

In another family, the story is even more depressing. Jacqueline's Thalidomide pension supports the whole family. But she is deaf, and nobody has taught her sign language. She could once write, but has forgotten how, and now sits endlessly watching the television, all but ignored by her family, locked away in her own world. It is a tale that an enraged Mat considers terribly neglectful.

Yet extraordinarily, back in Britain, Thalidomide may be making a comeback. Trials are underway to see if it can help in the treatment of everything from Rheumatoid Arthritis to cancer. James Herbert, who has Non-Hodgkin's Lymphoma, reveals that the drug has both alleviated his pain and shrunk his tumour. "I think it's a miracle drug." Could it be that 50 years after its arrival, this tragic drug is on the verge of a much more positive future?