Background: Phonological awareness tests are known to be amongst the best predictors of literacy; however their predictive validity alongside current school screening practice (baseline assessment, pupil background data) and to National Curricular outcome measures is unknown. Aim: We explored the validity of phonological awareness and orthographic measures, the Infant Index baseline assessment (Desforges & Lindsay, 1995), gender, free school dinners, and SEN status taken at age 5 in the prediction of English, Maths, and Science performance in Key Stage 1 of the National Curriculum in England. Sample: 435 children from nine schools in one Local Educational Authority (LEA) were screened at entry aged 4 or 5, and at 5:8, and age 7. Method: We trained schools Learning Support Assistants (LSAs) to administer orthographic and phonological awareness measures. Teachers collected data on all baseline and Key Stage 1 performance measures. Results: A series of 13 logistic regression analyses revealed that phonological awareness and orthographic knowledge best predicted 12 of 13 measures of performance at Key Stage 1. Additional variance was nearly always explained by SEN status. In 11 analyses the Infant Index baseline score predicted performance at age 7 and was the best predictor of maths test performance. Gender was an occasional additional predictor. Conclusion: School LSAs can be readily trained to administer phonological awareness measures to cohorts of 5-year-old children. Such measures used in conjunction with baseline measures significantly enhance prediction of Key Stage 1 performance. Deploying LSAs in this fashion significantly enhances a school's capacity to identify young children for whom additional support may be necessary.