Introduction: This review reports key metrics for the integrated UK National Health Service islet transplant programme including donor, transplant list, transplant activity and survival after islet transplantation. 
Methods: Data were obtained from the UK Transplant Registry on islet transplant activity between 1 April 2008 and 31 March 2016. Islet transplant function is measured by four key variables: graft survival, reduction in HbA1c, insulin requirements and annual rate of severe hypoglycaemic events. Metabolic outcomes (HbA1c, daily insulin requirement and the annual rate of severe hypoglycaemic events) are reported at one-year post-transplant for the period 1 April 2008 to 31 March 2015. Graft survival is reported one-year post-transplant for the period 1 April 2010 to 31 December 2015. Islet outcome data from the UK Transplant Registry are supplemented by data collected by the UK Islet Transplant Consortium. 
Results: On 31 March 2016, there were 28 patients on the UK active islet transplant list; a 22% decrease from the number listed one year earlier. Of those 31 patients registered on the list during 2015/16, 23% were male and the median (IQR) age was 50 (46-61) years. The national rate of declining pancreas islet offers from donation after brain death (DBD) donors for named patients from 1 April 2013 to 31 March 2016 was 45%.
For patients registered between 1 April 2010 and 31 March 2013, the median waiting time to islet transplant was 279 days and varied across centres: 146-594 days.
There were 31 islet transplants performed in the UK in 2015/16, a three-fold increase in the number performed in 2008/09 when islet transplants were first commissioned, and an increase of 35% compared to 2014/15. Of these 31 transplants, 25 (81%) were from DBD donors and 6 (19%) were from DCD donors.  
The Kaplan-Meier estimated one-year graft survival for the group of patients receiving one routine graft was 78% compared with 96% for the group receiving one routine and at least one subsequent priority graft.  There were statistically significant differences between the two groups, p=0.01. There was a reduction in median HbA1c from 64 mmol/mol prior to transplant to 51mmol/mol at one-year post-transplant. At one-year, 47 patients (57%) had an HbA1c less than 53mmol/mol. At one-year post-transplant there was a 54% reduction in median daily insulin dose from 0.52 to 0.24 units/kg. In the year post-transplant of the 79 patients with complete data, 62 (78%) experienced no severe hypoglycaemic events and 17 (22%) experienced between one and nine events.  The median annual rate of severe hypoglycaemic events prior to transplant, 9 events, was significantly reduced at one-year post-transplant to no events per year, p<0.0001. 
Conclusions: Comprehensive outcome reporting within a centrally commissioned, audited and governed national transplant programme has provided high-quality data for patients, medical staff and commissioners and will facilitate on-going performance review and quality improvement.