The EU’s chief negotiator set out the proposals thrashed out in protracted talks with the UK, including measures aimed at avoiding duties and quotas through a customs deal.

The envisaged close future relationship would make it “feasible” to strike a quick trade deal, he suggested.

At a news conference in Brussels, Mr Barnier also set out the contentious Northern Ireland backstop, aimed at avoiding a hard border with Ireland if there is no wider deal:

EU Chief Brexit Negotiator Michel Barnier. Picture: Emmanuel DUNAND / AFP/Getty Images

- If there was no final agreement at the end of the transition in 2020, there would be an “EU-UK single customs territory”.

- Northern Ireland would therefore remain in the same position as Great Britain, avoiding a customs border in the Irish Sea.

- Northern Ireland will remain aligned to the single market rules that are essential for avoiding a hard border.

- The UK would apply the EU’s customs code in Northern Ireland and would allow Northern Irish businesses to bring goods in to the single market without restrictions.

Brexit deal: What we know so far

Mr Barnier said the draft agreement made clear Northern Ireland would retain “unfettered market access to the rest of the UK”.

“For competition to be open and fair in such a single customs territory we have agreed provisions on state aid, competition, taxation, social and environmental standards,” he said.

“This will guarantee that both EU and UK manufacturing will compete on a level playing field.

“An essential condition for the single customs territory to cover fisheries and aquaculture products will be to agree between the Union and the UK on access to waters and fishing opportunities.”

Turning to the declaration on the future relationship, Mr Barnier said it proposed an “ambitious partnership, which we want, which is a free trade area based on regulatory and customs co-operation, in depth and with a level playing field”.

“Our objective is to abolish customs duties and quotas for all goods based on what we are proposing in the withdrawal agreement - a single customs territory,” he said.

There would be a new agreement on fisheries and sectoral agreements in transport and energy.

The future relationship would also cover justice, security and foreign policy co-operation.

He indicated it could be possible to agree the final trade deal within the transition period, due to expire at the end of 2020 - although it may be possible for that to be extended.

“I don’t think that these agreements will need as much time as were needed for other trade agreements with countries which were much further away in regulatory terms, in terms of standards, and also geographically,” he said.

“I think that it is feasible to construct the essentials of this future partnership within this short transition period, because we have got the basis.”

Mr Barnier said it was an “option” for the transition period to be extended by common agreement, but “we haven’t fleshed out” how that could be done.

Mr Barnier refused to be drawn on what would happen if MPs rejected the Brexit deal.

“The British discussion is very stimulating but I won’t make any comments,” he said.

“Mrs May said this is the best possible agreement in the current circumstances.”

Mr Barnier told reporters that “we have reached a crucial stage, an important moment in this extraordinary negotiation” but “the path is still long and may well be difficult” to achieve an orderly withdrawal and an “ambitious and sustainable partnership” .

Trade deal possible by the end of 2020, EU chief negotiator says