Brexit and European Tax Law

Here are some interesting questions. Well, I think them interesting anyway!
1. If we ‘do Brexit’, will we persist with VAT?
2. If so, how will it be administered, bearing in mind the current cross-border arrangements?
3. Will the European Court remain supreme, in terms of judicial opinion and interpretation?
4. On direct taxes, will we revert to double tax treaties, rather than the various European Directives?
5. If so, from what date?
6. If we do leave the EU, will the Courts go back to the ‘literal’ approach to interpreting tax legislation, a la Justice Rowlatt, or will it continue to dabble in the ‘purposive’ approach?
7. In the context of the above how would anyone define ‘The Purpose of Parliament’, in terms of (say) the formulae in the Emloyee Security/Benefit rules?
Je ne sais pas?
Opinions, s’il vous plait.