A £10 million research programme is to investigate why autistic adults are dying decades before their time.
The five-year project planned by the charity Autistica follows a bombshell study from Sweden that uncovered evidence of "shameful" premature death among people with the developmental disorder.
Researchers from the renowned Karolinska Institute analysed data on 27,000 people with autism and compared them with nearly three million non-autistic "controls".
They showed that, on average, autistic adults died 16 years younger than members of the general population. Those who also suffered from a learning disability died more than 30 years prematurely, at an average age of just 39.
Autistic people who were not held back intellectually died 12 years early, and even "high-functioning" individuals with good speech and language skills had double the normal risk of dying young.
Autistica's chief executive Jon Spiers said: "This new research confirms the true scale of the hidden mortality crisis in autism.
"The inequality in outcomes for autistic people shown in this data is shameful. We cannot accept a situation where many autistic people will never see their 40th birthday."
Speaking at a briefing in London, he added: "We aim to raise £10 million in the next five years to fund a major new programme of research in the UK looking at mortality in autism.
"That for us is a very significant sum of money - it's more than we've raised in our entire history as a research charity. But we believe there is a moral imperative to act and to understand better why people with autism are dying so young."
Autism is a lifelong disability affecting around 1% of the population that impairs a person's ability to communicate with and relate to other people.
As a "spectrum" condition, it impacts on people in different ways and has symptoms that range from mild to very severe.
A quarter of sufferers speak few or no words, only 15% will ever work full time, and almost 75% have at least one associated mental health condition.
Autism is estimated to cost the UK £32 billion per year, making it the single most expensive medical condition. Most of the cost is due to the need for life-long care.
The Swedish study led by Dr Tatja Hirvikoski was published in the online edition of the British Journal of Psychiatry in November last year.
Epilepsy and suicide emerged as two leading causes of premature death among autistic people.
Between 20% and 40% of autism sufferers were afflicted by epilepsy compared with 1% of the general population. And those without a learning disability had a nine times higher than average risk of killing themselves.
However, experts still have no clear idea why so many people with epilepsy die young.
Autistica has launched a campaign calling for more research collaboration to tackle the issue of premature death among autistic adults, and a national autism mortality review from the Government.
A petition backing the review demand will be delivered to Number 10 Downing Street later in the spring.
Mark Lever, chief executive of the National Autistic Society, said: "While this report is based on Swedish research, we have no reason to believe the situation would be that different here.
"Indeed, we fear it could be worse.
"The Government and national health authorities must urgently investigate what's going on in this country and start to put things right."