CA50320 | MEA: Qualifying expenditure: Exclusions from relief
From HM Revenue & Customs · Capital Allowances Manual
CAA01/S399 excludes certain expenditure from qualifying expenditure and lists a number of general exclusions for costs relating to:
the construction of works to be used mainly for the the subjecting of the raw product to a process, except a process designed for preparing the raw product for use as such (other capital allowances may be due instead),
buildings provided for occupation by, or for the welfare of, workers, except as provided by CAA01/S415,
construction of a building for use as an office (unless the expenditure on the part of the building used as an office was less than 10% of the expenditure on the construction of the whole building),
expenditure on the provision of plant and machinery, except as provided by CAA01/S402.