This part of GOV.UK is being rebuilt – find out what beta means

HMRC internal manual

Capital Gains Manual

Assets held on 6/4/65: historical cost

Where it is necessary on the disposal of an asset in whole or in part to trace its historical cost, the tracing and the calculation are to be carried out in accordance with the provisions for the computation of chargeable gains even where the relevant events occurred before 6 April 1965. See, for example, CG15590.