To determine the optimal dentoalveolar measure to assess unilateral cleft lip and palate (UCLP) patient models. To analyse the study models collected of five year old children with UCLP as part of Cleft Care UK (CCUK) to see if primary surgical outcome has improved since CSAG. Method: The models of 34 patients with UCLP taken at 5, 10 and 20 years were scored by two examiners on two occasions using five indices: the 5 Year Olds' (5YO); Goslon; Modified Huddart/Bodenham (MHB), Eurocran and Overjet. Reliability, predictive validity, agreement with gold standard, ease of use and time taken were recorded for each index/examiner. CCUK study models and intraoral photographs were scored using the 5YO index by two examiners on two occasions. These results were then compared to the original CSAG results. Results: Highest overall reliability was seen with MHB, followed by Overjet, 5YO and Goslon, with the latter more reliable in the mixed dentition. Predictive validity was similar for MHB, Goslon and 5YO with a 50%-65% prediction of final outcome from 5 and 10 years. Eurocran palatal index showed no clear predictive validity (Spearman's correlation=0.20). Agreement to 5YO at the 5 year age group was almost perfect for MHB and moderate for Goslon. Agreement to Goslon at 10 years was substantial for 5YO and moderate for oveljet and MHB. Time to score 34 models per index(mean in minutes): Goslon(13.4)< Overjet(13.6) 5Y0(19.4)< Eurocran(24.8)< MHB(27.4). Good outcomes accounted for 53% of all outcomes in CCUK (up from 30% in CSAG), whereas poor outcomes accounted for 19% (down from 36% in CSAG). Conclusion: As an outcome measure of UCLP models, only MHB and 5YO indices can be recommended for use at 5 years and Goslon at 10 years. Outcomes of primary surgery for UCLP have significantly improved in the United Kingdom since the original CSAG results were collected.