Autism is a baffling, solitary and deeply distressing condition that can imprison children in a silent, lonely world. Often unable to communicate with others, with difficulty expressing or reacting to emotion, those afflicted are strangers even to their own parents. Those severely affected cannot cope with ordinary life, are often unable to speak or even smile and can be swept by terrifying ranges of emotion, from rage to frustration, fear to helplessness. For parents, the burden is enormous. Many find the strain of trying to get through to autistic children draining. A sense of guilt and bewilderment in not knowing how to deal with autism puts other family relationships at risk, and many couples split up. The children themselves are often neglected — not physically, but mentally. Autistic children may be highly intelligent, but because few people know how to communicate with them, their minds lie idle.

TreeHouse, founded ten years ago to help children with severe autism, is a magnificent example of the determination of some parents to do more for those afflicted, and of how intensive and dedicated specialist therapy can bring extraordinary results, even for those thought to be untreatable. The school in North London has pioneered an Applied Behaviour Analysis (ABA) approach that yields substantial improvements in speech, social skills and in the children's ability to manage daily tasks. The therapy, however, is extremely costly. The ratio of teachers to children at TreeHouse is 1:1, and each class has five teachers and children. Though still in temporary premises, the school has 59 children, drawn from across London, and has plans for a purpose-built centre. TreeHouse, as a charity, relies on the voluntary sector and on the dedication of parents such as Nick Hornby, who today details the struggle to assist his son, Danny.

TreeHouse is seeking to become a national centre for innovation and best practice in the treatment of autism. The need is obvious; 588,000 people in Britain have some form of autism, with boys four times more likely to develop the condition than girls. A fifth of autistic children have been excluded from school. Autism is a lifelong disability, but there remains an opportunity for lifelong learning.

All families want to make Christmas a time of warmth and happiness, especially for their children. But it is especially galling that autistic children are often unable to share in the joy or even recognise the love with which their parents surround them. The care offered at TreeHouse will, however, make it just a little easier to bring their children out of their lonely world. And the more the pioneering therapies can be spread, the more children and families can be helped.

This is why The Times this year is asking for your help to support TreeHouse, the work it is pioneering and the research into this frustrating disability. Autism, it is feared, may be on the increase. Why this is so and whether genetic or environment factors play a part is largely unknown. What is known, however, is that dedicated and skilful carers and teachers can prevent what Nick Hornby calls the whirlpool that drags children down to a place where nobody can reach them. TreeHouse already helps other specialist schools; it needs £3 million to become a comprehensive centre for autism. We urge readers to do all they can to make this ambition a reality.