It's not really for defence
If the UK "Defence Budget" were an advertisement for a product then its title might well be considered illegal as a "false trade description." No doubt some of the budget is for defence, but past experience shows that money spent by the Ministry of Defence is actually used to engage in attacks on other countries - sometimes leading to considerable loss of life, big refugee problems, devastating damage to infrastructure, of doubtful legality under international law, hugely costly, and sometimes a great encouragement to terrorists to target this country. All this being action that is counter-productive to defence.
We need future defence budgets to be clearly set out as
spending for defence and
spending for war, ie attacking, bombing, invading other countries.
Would the British public support the latter if they knew what their money would be intended for?