As a member of the Local Government Pension Scheme you have to be contracted out of the State Second Pension (S2P) (previously known as State Earnings Related Pension Scheme (SERPS)). On attaining State Pension Age a Notice of Entitlement to a Guaranteed Minimum Pension (GMP) may be issued, showing an entitlement to a weekly amount of GMP. This GMP is a substitute for the additional State Pension you would have earned had you not been contracted out of the State Scheme. A GMP is not additional to the pension from the Berkshire Pension Fund. It is the minimum amount of pension that the Berkshire Pension Fund must pay.
The GMP element of your pension is split between that earned from 6.4.78 to 5.4.88 and that earned from 6.4.88. Increases due on the pre 6.4.88 element are paid with your state pension. The first 3% of any increases due on the post 5.4.88 element is paid by the Berkshire Pension Fund, the balance, if any, is also paid with your state pension.