This expenditure equates to about a one thousandth of a penny from each tax payer.
*Pedant Alert*
That would equate to 15 Billion UK income tax payers, or roughly twice the entire global population. The true figure is a shade under half a penny per individual income tax payer (30.3m UK income tax payers).
Your underlying point (it's not a great deal of money in macro-economic terms) is, of course, correct.