An investigation was carried out into the effect of inclusion in a Total Communication or Sign Bilingual programme upon deaf children's written English, based upon the theory of linguistic interdependence (Cummins, 1991). The relationship between each child's identification with British Sign Language (BSL) and their subsequent test scores was also examined. Seven participants from Sign Bilingual schools and six participants from Total Communication schools were administered the Writing Assessment Task (Burman et al, 2007). Participants in the Total Communication group scored significantly higher on overall test score ( U = 5.500, Z = -2.220, p<0.05) as well as on the subsection of Story Development (U = 5.000, Z = -2.338, p<0.05). However, no significant difference was found for the Grammatical subsection (U = 8.500, Z = -1.801, p>0.05). No significant difference was found between those participants who indicated BSL to be their preferred language and those who indicated English or a mixture of English and signing; however, a non-significant difference was shown. The results are discussed in relation to the linguistic interdependence theory and it is suggested that although the study cannot conclusively demonstrate transference of linguistic skills between signed and spoken languages, the trend towards those participants who prefer BSL scoring higher cannot be ignored. The usefulness of the labels 'Total Communication' and 'Sign Bilingualism' is also discussed and it is argued that the dichotomy in theory does not stand up in practice. The need to make an explicit distinction between BSL and Sign Supported English is suggested to be paramount to the progression of deaf education and the availability of both in complete and grammatically correct forms an immediate priority.