The NHS complaints procedure is the statutorily based mechanism for dealing with complaints about NHS care and treatment and all NHS organisations in England are required to operate the procedure. This quarterly collection is a count of written complaints made by (or on behalf of) patients, received between 1 January 2017 and 31 March 2017. Previous quarterly data will also be included. This information is classified as experimental. Data are published at national, regional and organisational levels for certain organisations.