Customs when leaving the United Kingdom
This page explains that some visitors to the United Kingdom can qualify for a refund of value added tax (VAT) paid on goods purchased during their stay.
For full details of who qualifies for a refund and how to get it, see the guidance on VAT refunds for travellers departing from the European Community (EC)
on the website of HM Revenue & Customs.
If you wish to claim a refund as you leave the United Kingdom, most ports and airports have signs directing travellers to customs. If not, you should ask airport or port staff to direct you to the Customs VAT Reclaim Office.
More information about finding customs on departure is on the website of HM Revenue & Customs.