Value Added Tax (VAT) – Import VAT is charged at the same rate that applies to similar goods sold in the UK and applies to commercial goods over £18 in value, and on gifts that are over £40 in value. The value of the goods for import VAT is based on the:
basic value of goods, plus
postage, packing and insurance, plus
any import (Customs or Excise) duties charged
Customs duty – Customs duty becomes payable if the goods are over £135 in value but is waived if the amount calculated is less than £9. Customs duty is usually charged as a percentage of the value of the goods.
http://www.hmrc.gov.uk/customs/post/buying.htm