It's not the budget. It's the hidden cuts to services, the declining maintenance to infrastructure, the privatization of essentials. Those are the licks they take from the pot, while they tell you the pot is still full.
Apologies but what money is spent on in the UK is public information —- it is part of the budget. The fat cat and the hoodwinked mouse is a poor metaphor.
I really like your metaphor, but it is misleading.