LONDON (REUTERS) - The European Union is offering Britain a "relatively low quality" trade agreement, chief British negotiator David Frost said in a letter to his European Union counterpart Michel Barnier on Tuesday (May 19).

Britain left the EU at the end of January and is now seeking to negotiate a free trade deal with the bloc.

Talks have reached an impasse however, with both sides trading barbs before a crunch meeting next month.

The British government published its draft legal texts for an agreement on Tuesday.

While they had previously been shared with the EU team, Britain said it was making them public as a "constructive contribution to the negotiations".

In a letter published alongside the texts, Frost said Britain had drawn on precedent in recent agreements between the EU and other countries.

Brussels has argued a wider deal is needed to take into account Britain's proximity to the bloc.

"We find it perplexing that the EU, instead of seeking to settle rapidly a high-quality set of agreements with a close economic partner, is instead insisting on additional, unbalanced, and unprecedented provisions in a range of areas, as a precondition for agreement between us," Frost wrote.

"What is on offer is not a fair free-trade relationship between close economic partners, but a relatively low-quality trade agreement coming with unprecedented EU oversight of our laws and institutions."

Frost said he remained convinced it would be "very straightforward" to come to an agreement quickly.

The two sides have given themselves until the end of June to assess progress and decide whether to extend negotiations beyond the end of 2020, something Britain has so far refused to do.