Changes made by Pensions Increase (Local Authorities' etc. Pensions) 1989
S.I. 1989/417
Made to Pensions Increase (Local Authorities' etc. Pensions) 1974
3 changes. All changes made by Pensions Increase (Local Authorities' etc. Pensions) 1989
From legislation.gov.uk's record of changes, the official one: see it there.