 A sequel , Quatermass II , was accordingly commissioned in 1955 , but Reginald Tate died of a heart attack only a month before production was due to begin . With very little time to find a replacement , John Robinson was picked as the only suitable actor available . Robinson was uncomfortable about taking over from Tate and with some of the technical dialogue he was required to deliver , and his performance has been criticised as " robotic " , although others such as Andrew Pixley in Time Screen Magazine praised Robinson for doing compelling work after the initial episode of the serial . 
