It comes after Michel Barnier and David Davis failed to make any significant progress on Brexit talks earlier this week, with the divorce bill Brussels expects Britain to pay being a major sticking point in negotiations.
Mr Barnier reportedly claimed there were “joint obligations towards third world countries” and that money should be given to Ukraine and development programmes in Africa, the Caribbean and Pacific countries.
He claimed it would not be fair if other member states have to pick up the shortfall in funds left by Britain leaving the seven-year budget agreement, set to finish in 2020 and with Britain set to leave the EU in 2019.
The EU chief negotiator said: “We have jointly committed to support innovative enterprises and green infrastructure in European regions until 2020.
“These are not recognised by the UK as legal obligations. With such uncertainty, how can we build trust and start discussing a future relationship? We need to address together these issues seriously and rigorously.”
The projects include building defences to prevent flooding and protect wildlife. Such developments undertaken by the EU include building animal bridges, creating fish ladders to help species move upstream and planting hedgerows.
The UK currently gives the EU €1 billion of the €15 billion in total that Brussels splurges on development aid.
Mr Barnier’s demands were slapped down by Tory backbencher Jacob Rees-Mogg.
Mr Rees-Mogg said: “Unless this is a straw man that the EU expects to negotiate away, it shows exceptional naivety to think that a British government could agree to this. Once we have left, the EU can waste money all by itself.”
Britain would meet its legal obligations, Mr Davis said, but that they must be “real obligations”.
He added: “We have a duty to our taxpayers to interrogate it rigorously. It’s fair to say across the piece we have a very different legal stance but… the settlement should be in accordance with EU law and in the spirit of the UK’s continuing partnership with the EU.”
It comes after EU bigwig Guy Verhofstadt took aim at Britain’s Brexit negotiating team, shooting down David Davis’s claims that Brussels’ approach to talks are inflexible.
Britain’s Brexit Secretary has called for a less rigid approach to negotiations, but Guy Verhofstadt claimed the EU has bent over backwards to accommodate the UK while a member of the sprawling European superstate.