BACKGROUND: Increased demand for access to specialist services for providing support to children with speech, language and communication needs prompted a local service review of how best to allocate limited resources. This study arose as a consequence of a wish to evaluate the effectiveness of an enhanced consultative approach to delivering speech and language intervention in local schools. AIMS: The purpose was to evaluate an intensive speech and language intervention for children in mainstream schools delivered by specialist teaching assistants. METHODS and PROCEDURES: A within-subjects, quasi-experimental exploratory trial was conducted, with each child serving as his or her own control with respect to the primary outcome measure. Thirty-five children between the ages of 4;2 and 6;10 (years; months) received speech and/or language intervention for an average of four 1-hour sessions per week over 10 weeks. The primary outcome measure consisted of change between pre- and post-intervention scores on probe tasks of treated and untreated behaviours summed across the group of children, and maintenance probes of treated behaviours. Secondary outcome measures included standardized tests (Clinical Evaluation of Language Fundamentals - Preschool(UK) (CELF-P(UK)); Diagnostic Evaluation of Articulation and Phonology (DEAP)) and questionnaires completed by parents/carers and school staff before and after the intervention period. OUTCOME and RESULTS: The primary outcome measure showed improvement over the intervention period, with target behaviours showing a significantly larger increase than control behaviours. The gains made on the target behaviours as a result of intervention were sustained, when reassessed 3-12 months later. These findings were replicated on a second set of targets and controls. Significant gains were also observed on CELF-Preschool(UK) receptive and expressive language standard scores from pre- to post-intervention. However, DEAP standard scores of speech ability did not increase over the intervention period, although improvements in raw scores were observed. Questionnaires completed before and after intervention showed some significant differences relating to how much the child's speech and language difficulties affected him/her at home and at school. CONCLUSIONS and IMPLICATIONS: This exploratory study demonstrates the benefit of an intensive therapy delivered by specialist teaching assistants for remediating speech and language difficulties experienced by young children in mainstream schools. The service delivery model was perceived by professionals as offering an inclusive and effective practice and provides empirical support for using both direct and indirect intervention in the school setting.