There is no single method of apportioning household bills and expenses and so on into business and personal. HMRC does not prescribe a particular method, although there are some examples listed on their website. So, you might apportion your bills on:
- floor area or number of rooms
- time spent
- usage
or some appropriate and reasonable combination of the three.
The sorts of expenses that may be allowable for tax are:
- Council Tax
- mortgage interest,
- insurance
- water rates
- general repair
- rent
- heat
- light
- electricity
- telephone (incl a proportion of the line rental)
- broadband.
Alternatively, £3/week (from 2008-09) would be allowable without specific receipts/evidence, or if it’s deemed that business use is minimal.
