Polly Toynbee was on BBC1's Question Time last night, and she said:
We saw child poverty in this country -- and this is all there in this document -- go from 14% in 1979 to 33%
[you can watch it online here -- quote comes at about minute 38]
She's used these figures before, of course, without noting the inconsistency between the two series from which the numbers are taken. However, it's not "all there in this document" which actually says:
The growth of child poverty on the relative measure was particularly alarming, with a rate of 12% in 1979 rising to 27% by 1992.
[.doc link here]