If your capital is between the lower and upper limits, a ‘tariff income’ is assumed, ie your capital is treated as if it were generating income. Normally, £1 a week for every £250 (or part of £250) above the lower limit is included as income in this way. For instance, if you have capital of £6,300, £2 a week is included as income. Each time capital moves into the next block of £250 (even by as little as 1p) an additional £1 a week is included as income. This tariff income is then added to your other income when calculating entitlement to the benefit.

If you (or your partner) have reached pension age (and are not claiming universal credit), the assumed tariff income is £1 for every £500 (or part of £500) above the lower limit.
HB Regs, reg 52 ; HB(SPC) Regs, reg 29(2)

If tariff income is included in your assessment, let the local authority know if the amount of your capital changes. If your savings drop to the next lower tariff income band and you have not told the loca