Capital Gains Tax (CGT) is a tax on the “gain” or profit you make when you sell, give away, or otherwise dispose of something. It applies to assets that you own, such as shares or property. There's a tax-free allowance and some additional reliefs that may reduce your Capital Gains Tax bill. Sometimes you may have no tax to pay.
CGT is currently paid at a rate of between 18% and 28% for individuals, depending on the level of the gains, and any other taxable income.
As an individual you are also entitled to an annual Capital Gains Tax-free allowance of £11,000 for the 2014/15 financial year.