You asked
The deaths of prison inmates in the UK between 2010 to 2020 that have involved new psychoactive substances.
We said
Thank you for your enquiry relating to the deaths of prison inmates in the UK between 2010 to 2020.
The data shown in the following publication is the only information we hold regarding deaths of those in prison custody: Drug-related deaths and suicide in prison custody in England and Wales: 2008 to 2016. This publication was created using data provided by HM Prison Service (HMPS). Therefore, we recommend contacting them with your FOI request, as they would be best placed to answer. They can be contacted via email at public.enquiries@noms.gsi.gov.uk.
The Ministry of Justice are also responsible for the collection and publication of data on deaths in prisons in England and Wales, whilst the Scottish Government and the Northern Ireland executive are responsible for the equivalent information pertaining to their jurisdictions. They can be contacted at the following addresses:
Ministry of Justice: data.access@justice.gov.uk
Scottish Government: ceu@gov.scot
Northern Ireland Executive: foi@justice-ni.x.gsi.gov.uk