The UK companies concerned must act quickly: the request to appoint a fiscal representative must be filed with the competent authorities before the date of Brexit (currently 30/03/2019, although it seems that some margin for a possible delay might have been created during the last negotiations). As all these files cannot be treated immediately by the tax authorities, they allow themselves 6 months to handle these files. During this period, the current direct VAT registration will be deemed to be converted into a VAT registration number with a fiscal representation. 

Please note that being identified via a fiscal representative alters the VAT regime on some incoming transactions. Some compulsory national Belgian VAT reverse charge rules become applicable if the buyer is identified for VAT purposes via a fiscal representative.  

Moore Belgium has extensive experience in handling VAT files as a Belgian fiscal representative. Do not hesitate to contact our Belgian VAT team if you would like our assistance as your fiscal representative.