A therapy to improve the communication skills of children with autism before they get to school is being tested.
The study aims to reach children before they go to school
The Medical Research Council is funding a four-year University of Manchester project to explore new ways for parents and autistic children to communicate.
The families of 144 children will be asked to develop languages using signs, pictures and symbols during fortnightly therapy sessions for six months.
The sessions will then be followed up with six monthly "booster" meetings.
It is hoped the study will improve the child's social and language skills by the time they start school.
In the UK six children in 1,000 have autism, a developmental disability which affects the way someone communicates and interacts with other people.
Pilot studies had already shown the therapy is effective and this clinical trial will involve 144 children in Manchester, Newcastle and London.
Lead researcher Dr Jonathan Green said: "We hope that it will provide a new evidence base for autism service planning and help to change the face of service provision both in the UK and overseas.
"Because the treatment helps communication, it improves a parent's sense of competence and involvement with their child, as well as the child's development."
The MRC is also funding a second study on Asperger's Syndrome, a condition often considered to be a mild form of autism, which is characterised by social aloofness and a lack of interest in other people.
The research will be exploring why adults with the syndrome have a good memory for facts, but less effective recall for how they fit into remembered events.
The researchers hope that by improving understanding of the condition, doctors will be able to draw up better treatment and educational programmes.
MRC chief executive Professor Colin Blakemore said he hoped the studies, which are receiving £1.5m, would provide "solid foundations" for developing autism treatments.
"There has been very little systematic research into effective treatments for autism.
"Furthermore, we hope that this significant investment across a diverse set of projects will provide long-term benefit by supporting an increase in the UK research capacity in this area."
And Richard Mills, director of research at the National Autistic Society, added the research was badly needed.
"There is a shortage of independent scientific study into interventions, despite the large numbers of approaches available.
"Too little activity has been devoted to the evaluation of the various interventions and therapies in use."