This is fairly complex. The rate of tax paid by individuals depends on whether they are a basic or higher rate taxpayer (the threshold being £39,825 for the tax year to 5 April 2008).

It also depends on the length of time the asset has been held. A capital gain is reduced by Taper Relief. There are two types of Taper Relief, one for business assets and one for all other assets. For business assets the gain is reduced by 50% for assets owned for over 12 months and by 75% for assets held for over 24 months. For all other assets the gain tapers by 5% for each full year of ownership from the third year to the tenth year, eventually exempting 40% of the gain after the full decade of ownership (i.e. for a higher rate taxpayer, each 5% taper of the gain reduces the rate of tax by 2%). 

Business assets most commonly held by Barnes Roffe clients tend to be: shares in trading companies; interests in partnerships; properties rented to trading businesses for use in their trade; and some AIM shares. Note that the rules defining business assets for shares and property changed in 2000 and 2004, so some assets have a mixed period of ownership where they qualified as business and non-business assets. This makes the calculation complicated.

Finally, for some assets held before March 1982, you can calculate the gain by reference to the March 1982 value plus indexation uplift (i.e. not the original cost). This will usually reduce the gain.