Where possible higher rate taxpayers should “Gift Aid” any payments to charity to provide additional benefit to the charity and for the individual to obtain additional tax relief on the payment.
For example where an individual makes a £20 cash donation to charity the charity is able to reclaim a further £5 from HMRC making a gross gift of £25. Where the individual is a 40% higher rate taxpayer he or she is able to claim a further £5 tax relief under self-assessment, reducing the net cost of their donation to £15.
Note that the donor is required to make a declaration that they are a UK taxpayer and those that have not suffered sufficient UK tax to support the Gift Aid amount will taxed on the shortfall.
Remember that Gift Aid does not just apply to gifts of cash. Many charity shops will now sell the donated items on your behalf and are able to treat the sale proceeds as Gift Aided donations.
It is also possible to gift quoted securities and land and buildings to charity and claim Gift Aid on the market value of those assets.