should i account for business expenses on the day that i am billed or on the day that i pay the bill?

Question

i am trying to do my UK self assessment tax return self employment pages

Am I required by law to do one or the other?

Answer 1

on the day you were billed is when the expense was incurred for tax purposes.

Answer 2

In accounting there is something called the matching principle which state that an expense should be recorded when it is incurred as that will give you a more accurate picture of your profits and losses.
For taxes that what is done

Answer 3

Pretty sure it's when you are billed. That's what i'm doing!