Castle Point Council’s policy team has produced a superb tax credits practice note, and the following metaphor is a direct steal from it so credit where it’s due.

In the case under discussion here, the claimant was given a sack of 100 apples at the start of the year. 75 were Granny Smiths and 25 were Cox’s. In February, the Inland Revenue decided that they had given her too many Cox’s: she should only have had 5 of those. Unfortunately, she only had one Cox’s apple left in the sack, as well as 25 Granny Smiths. So the IR took back the one remaining Cox’s and 19 of the 25 remaining Granny Smiths, leaving the claimant with just 6 Granny Smiths to eat until the end of the year.

The claimant cannot survive on 6 apples, so as a temporary stop-gap the IR will give her 10 pears to keep her going until the end of the year.

The simple and straightforward task for HB and CTB assessors is this: calculate exactly, to the nanogram, how many bananas per week the claimant now has in her sack.