The provision for this exclusion is within paragraph 8(1) – (4) of Schedule 6 to the Finance Act 2000.
Excluded supplies: supply for domestic or charity use
8. (1) A supply is excluded from the levy if it is
(a) for domestic use (see paragraph 9), or
(b) for charity use.
(2) For the purposes of this paragraph, a supply is for charity use if the commodity supplied is for use by a charity otherwise than in the course or furtherance of a business.