Section 3 of the Taxation of Chargeable Gains Act 1992 (c.12) (“TCGA”) provides that an individual shall not be chargeable to capital gains tax in respect of so much of his taxable amount for any year of assessment as does not exceed the exempt amount for that year. Subsection (2) specifies the annual exempt amount (“AEA”) as £11,300. Subsection (3) provides that if there is an increase in the consumer prices index (“CPI”) that is deemed by subsection (3A) to be a relevant increase, the AEA is increased in relation to a tax year by reference to a formula prescribed by subsection (3B) unless Parliament otherwise determines.