Specific deductions: pre-trading expenditure: relief
You should check the other guidance available on GOV.UK from HMRC as Brexit updates to those pages are being prioritised before manuals.
S57 Income Tax (Trading and Other Income) Act 2005, S61 Corporation Tax Act 2009
Relief under the above legislation in respect of pre-trading expenditure is only available to the person who incurred the expenditure and commences the trade.
The qualifying pre-trading expenditure is treated as incurred on the day on which the trade, profession or vocation is first carried on. It therefore enters into the calculations of the profit or loss for the first year of assessment in which the trade profession or vocation is first carried on. No separate claim for loss relief is required.
There are separate rules for pre-trading expenditure incurred by companies which falls into the loan relationship rules. See CFM32100 for more details.