The general trend that emerges is that, when the government increases spending, as it has since 2015‑16, the bureaucratic machine often has difficulty keeping up. When the government is in a period of expansion, it is difficult for the bureaucratic machine to spend to the same extent. Typically, it is during these times that we see an increase in lapsed funds. Conversely, when times are tougher, government spending growth is lower and lapsed funds tend to decrease. This seems to be consistent with the size of government.
On December 1st, 2022. See this statement in context.