"To be completely frank with you ... there are many divergences, and they are very serious divergences, which is probably quite natural", Barnier told reporters.
The fishery issue is one of the stumbling blocks, according to Barnier. The UK wants a separate deal on fisheries to be renewed every year, something Barnier called "impractical".
"The United Kingdom does not want the fisheries agreement to be part of our economic agreement, it wishes to negotiate reciprocal access to British waters and European waters on an annual basis, which, and I can say this as a former fisheries minister amongst other things for my country, it's not practicable", he said.
According to the senior official, London wants a number of separate agreements, while the EU is seeking a single agreement.
Britain and the European Union launched post-Brexit negotiations on Monday, 2 March, to flesh out the future relationship between the two sides on multiple issues, but most importantly, trade and security.
The fishery deal still remains the main acute point of the talks. The European Union wants to retain access to British waters to fish there. However, British prime minister Boris Johnson has insisted that “taking back control” over the UK’s waters is a key Brexit objective and said Britain will become an "independent coastal state".