Since 5 October 2015, large shops in England have been required by law to charge 5p for all single-use plastic carrier bags. They are required by law to report certain information to Defra, and they provide other information on a voluntary basis.
These publications summarise the data collected by Defra for:
the first 6 month reporting period - from 5 October 2015 to 6 April 2016
the first full year - from 7 April 2016 to 6 April 2017
the second year - from 7 April 2017 to 6 April 2018