Mr Barnier seems to think the UK will not settle what it owes. That is a misunderstanding. The UK government has always made clear it will honour its legal obligations. It will, for example, pay around £30 bn of additional net contributions to the EU for the near 3 year period of transition from our vote to leave to our exit in March 2019. That is a big win for the EU, given the fact that the UK Parliament could have moved to implement the referendum decision quickly and unilaterally to end our contributions much earlier. We could have renounced the EU Treaty instead of complying with it by sending an Article 50 letter. We chose the friendly route of leaving instead. It gives them plenty of time to adjust their budgets for after our departure. The problem for Mr Barnier is there is no legal or Treaty power to levy money on us after we have gone, and no legal requirement for us to co fund their budget after 2019.
As Mr Barnier and his colleagues are usually sticklers for the law of the Treaties, he should get on with implementing the various clauses in the EU Treaties requiring the EU to have close and friendly relations with neighbouring countries, and to promote trade between them. That of course is what businesses and many voters on the continent want him to do, as they want best possible access to the lucrative UK market.
It does sound as if the EU has been doing some homework on the lack of UK Ministerial powers to make ex gratia or additional payments to the EU above and beyond the legal and required contributions whilst we are a member. I see they are now talking about the UK paying money to low income third countries as overseas aid. UK Ministers do of course have powers to make overseas aid payments to such countries. The good news is we are already making large payments under this heading, so the EU might be able to take that into account to help it move on to the important issues over our future relationship.