The Brexit has been decided on by the British population (at least a majority of those who went to the ballots). There has been a lot of consequences on economics and politics which have been discussed in the media and which will require a lot of political decisions and negotiation in the coming years.
Here is my opinion on the Brexit tax issues raised and maybe not yet thought about.
Application of EU-Directives
In direct taxes, the most important one will be the application of the EU Parent-Subsidiary Directive (PSD). Dividends paid by German or French companies to their UK parents may become subject to withholding tax in Germany or France. Currently, it is the PSD which prevents such payments from withholding taxes. No longer covered by the PSD, dividends will be subject to tax at rates of 5% (treaty rate for important shareholdings). The UK as a holding hub for multinational groups risks to lose some attractiveness.
VAT and Custom duties
Today services rendered and good delivered to and from the UK are intra-community deliveries/services for VAT purposes. After the Brexit, the same should qualify as third country transactions. As a consequence, the underlying exemption rules change together with the required documentation. Goods delivered to the UK will further on require the same documentation as deliveries to Switzerland.
Custom duty exemptions existing for goods delivered between different EU member states may no longer apply (depending on the Brexit conditions negotiated with the EU).
Considering the high level of compliance required especially for VAT, many procedures in international trade will need to be adapted (re-adapted to times before 1993). Does this mean that the step into the future, which the Brexit was supposed to be for the UK, implies a step back in time of more than 20 years?
UK Treasury (supported by Inland Revenue) and the European politicians may discuss and negotiate an outcome of tax rules and special status of the UK which replace the old system with equivalent rules. Depending on the outcome of such negotiations, the above consequences may not occur. Who knows?