There are probably definitions of these things somewhere that clear up the confusion but the close jaxtaposition of these two factoids [from a Reuters page of October stats from the ONS], both using 'since 1984' stood out:
Still, the more internationally-recognised ILO measure of the unemployment rate in Britain fell to 4.7 percent in the three months to August, the lowest since comparable records began in 1984.
and
The ONS also said the number of inactive people of working age rose by 91,000 on the quarter to 7.93 million, the highest figure since this series began in 1984.
I wonder what the official definition of full-employment is - its what the govt seem to keep claiming we have.