VATREG23350 - Voluntary registrations: persons who do not make or intend to make taxable supplies in the UK: 8th and 13th Directives
An overseas trader who has no establishment in the UK cannot register for VAT under the provisions of this section. If the overseas trader is registered for VAT in another Member State of the EU or is in business outside the EU, they may be able to recover UK VAT under the EU 8th or 13th VAT Directives, (see Notice 723A Refunds of VAT in the European Community for EC and non-EC businesses).
Advise overseas traders who do have an establishment in the UK, but who have opted not to be registered on the grounds that their anticipated input tax recovery will be less than £500 a year, that they may seek recovery of input tax under the EC 8th / 13th VAT Directive, as appropriate.