CGT and RPI following demerger

I owned shares in Uniq plc prior to the demerger of Wincanton from Uniq in May 2001. Following the demerger, I calculated the base cost of my new Wincanton shares in accordance with percentages provided by Uniq in November 2001. This base cost calculation included an RPI allowance. It is likely I will be selling my Wincanton shares in the near future. Please can you advise if I should be using the base cost so established in 2001 or if I need to back out the RPI allowance for the purposes of capital gains tax.

Hi brian bostock,
The guidance at CG17207 advises that following the simplification of Capital Gains Tax.
Disposals on or after 6 April 2008 do not attract indexation.
You should use the base cost in calculating Capital Gains tax.
Please see guidance here:
CG17207 - Indexation: history
Thank you.