This study examined the relative importance of a number of cognitive factors (i.e. working memory, vocabulary knowledge, general cognitive ability and reading skills) in accounting for differences in the rate of progress made by children in the development of emergent writing skills. Sixty-seven children were assessed on tasks measuring the visuospatial, phonological and central executive components of working memory. The children's written texts were analysed according to the assessment scale for writing from the Early Years Foundation Stage Profile. The results indicate that reading performance and visuospatial memory skills are crucial to determining whether or not children aged 4–5 years are able to meet the UK government's prescribed educational standards for writing. The importance of visual skills in the acquisition of orthographic knowledge and writing conventions gained through reading is discussed in relation to current instructional strategies within schools.