@Walter Hinteler,
Foreign minister has been offered EU Lisbon Treaty tuition in English by Germany's finance minister. Wolfgang Schäuble derided the Brexit advocate for denying linkage between the single market and free movement. [Schäuble is "known for his 'English'.]
Foreign Secretary Johnson had suggested that once Britain left the EU it would still have free access to the single market.
Article 3 of the Lisbon Treaty says the Union shall provide free moment "without internal frontiers" while also establishing an internal market, without discrimination, but with respect for cultural diversity.
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And another point, which hasn't got a got attendance so far:
Northern Irish legal challenge to referendum to involve Attorney General: all the implications of leaving the EU specific to Northern Ireland will be examined by a judge at a preliminary hearing at the High Court in Belfast.