Johnson’s Brexit vision is ‘impossible’
The foreign secretary reportedly told a Czech paper the UK was likely to leave the EU customs union post-Brexit - but still wanted to trade freely after.
However, Jeroen Dijsselbloem, the Dutch finance minister, said such an option "doesn't exist" and was "impossible".
Number 10 said a decision on membership of the customs union had not been made.
Mr Johnson reportedly told the Czech newspaper Hospodarske Noviny he did not believe the UK would remain in the EU customs union after Brexit.
He was quoted as saying he believed such a move could be done while "maintaining free trade" with EU states, suggesting the UK could remain within the single market.
The customs union allows members to move goods without the imposition of tariffs on each other.
However, all members also have to apply the same tariffs to goods that are imported from outside the union - which is seen as a disadvantage by some Brexit supporters who want the UK to be able to negotiate its own deals.