We present SignSynth, a fully automatic and holistic approach to generating sign language video. Traditionally, Sign Language Production (SLP) relies on animating 3D avatars using expensively annotated data, but so far this approach has not been able to simultaneously provide a realistic, and scalable solution. We introduce a gloss2pose network architecture that is capable of generating human pose sequences conditioned on glosses. 1 Combined with a generative adversarial pose2video network, we are able to produce natural-looking, high definition sign language video. For sign pose sequence generation, we outperform the SotA by a factor of 18, with a Mean Square Error of 1.0673 in pixels. For video generation we report superior results on three broadcast quality assessment metrics. To evaluate our full gloss-to-video pipeline we introduce two novel error metrics, to assess the perceptual quality and sign representativeness of generated videos. We present promising results, significantly outperforming the SotA in both metrics. Finally we evaluate our approach qualitatively by analysing example sequences.