http://www.legislation.gov.uk/ukpga/2001/2/part/2A/chapter/4Capital Allowances Act 2001An Act to restate, with minor changes, certain enactments relating to capital allowances.2001-04-05texttext/xmlenStatute Law Database2026-05-01Expert Participation2026-05-01 Capital Allowances Act 2001s. 774E(5)(b)Finance Act 2008Sch. 20 para. 12(11)Capital Allowances Act 2001s. 29(1A)The Fire and Rescue Services (Northern Ireland) Order 2006Sch. 3 para. 24(b)art. 1(3)art. 2Capital Allowances Act 2001s. 436(2)(aa)Planning (Consequential Provisions) (Wales) Act 2026Deddf Cynllunio (Darpariaethau Canlyniadol) (Cymru) 2026Sch. 2 para. 329(b)Sch. 5 Pt. 1s. 5(2) PART 2ACHAPTER 4270DA1The relevant interest in relation to any qualifying expenditure is the interest in the building or structure to which the person who incurred the expenditure on its construction was entitled when the expenditure was incurred.2Subsection (1) is subject to the following provisions of this Chapter and to sections 270FB (highway undertakings) and 270IG (provisions applying on termination of lease).3If—athe person who incurred the expenditure on construction was entitled to more than one interest in the building or structure when the expenditure was incurred, andbone of those interests was reversionary on all the others,the reversionary interest is the relevant interest.4For the purposes of section 270AA(2), on the sale of the relevant interest in a building or structure, the seller (and not the purchaser) is treated as the person who has the relevant interest on the day of transfer.270DBFor the purposes of determining the relevant interest, a person who—aincurs expenditure on the construction of a building or structure, andbis entitled to an interest in the building or structure on or as a result of the completion of the construction,is treated as having had that interest when the expenditure was incurred.270DC1An interest does not cease to be the relevant interest merely because of the creation of a lease or other interest to which that interest is subject.2This is subject to section 270DD (leases granted for 35 years or more).270DD1This section applies if—aqualifying capital expenditure has been incurred on the construction or acquisition of a building or structure,ba lease of the building or structure is granted out of the interest which is the relevant interest in relation to the qualifying expenditure, andcthe effective duration of the lease is equal to, or exceeds, 35 years.2If the market value of the retained interest in the building or structure is less than one third of the capital sum given as consideration for the lease—athe lessee is treated, for the purposes of this Part, as acquiring the relevant interest in the building or structure on the grant of the lease, andbon the expiry or surrender of the lease, the lessor is treated, for the purposes of this Part, as acquiring the relevant interest from the lessee.3The capital sum given as consideration for the lease is treated for the purposes of subsection (2) as excluding the amount, in respect of any premium required to be paid under the lease, that is brought into account as a receipt in calculating the lessor’s profits for the purposes of ITTOIA 2005 or CTA 2009 (determined in accordance with section 277 of ITTOIA 2005 or section 217 of CTA 2009).4For the purposes of this section, the “effective duration” of a lease is to be determined in accordance with section 303 of ITTOIA 2005 or section 243 of CTA 2009.270DE1Subsection (2) applies if the relevant interest is a leasehold interest which is extinguished on the person entitled to the interest acquiring the interest which is reversionary on it.2The interest into which the leasehold interest merges becomes the relevant interest when the leasehold interest is extinguished. S. 45H(2) modified (with effect in accordance with s. 167 of the amending Act) by Finance Act 2003 (c. 14) , Sch. 30 para. 7 Pt. 2A inserted (5.7.2019) by The Capital Allowances (Structures and Buildings Allowances) Regulations 2019 (S.I. 2019/1087), regs. 1, 2