Retrieved from <a href="http://www.legislation.gov.uk/uksi/1999/991/contents" target="_blank">http://www.legislation.gov.uk/uksi/1999/991/contents</a> [accessed 20 July 2017] which sets out how entitlement can change (and from what date) if, amongst other situations:
an advantageous change of circumstances is reported late by a claimant
the Secretary of State disagrees with a tribunal’s decision
the courts give a new interpretation of the criteria to be awarded a benefit
the law is changed to alter the entitlement conditions of a benefit
a decision was made in ignorance of a claimant's true circumstances, but they could not reasonably be expected to have known that the decision was incorrect.4CPAG. (2017). Welfare Benefits and Tax Credits...