THERESA May has been warned not to “trade away” UK fishing rights after the EU made a bold pitch to maintain its current access to British waters even after the transitional deal ends in December 2020.

The move by Brussels was denounced by Ukip as an attempt at “daylight robbery” while the Scottish Fishermen’s Federation dismissed it as “absurd” and urged the likes of Jean-Claude Juncker, the European Commission President, to think again.

The Prime Minister left the latest summit of EU leaders upbeat after they ratified the deal on the so-called Implementation Period, which will last 21 months from Brexit Day in March 2019.

The EU27’s seven-page negotiating document said its guidelines were designed to deliver a "balanced, ambitious and wide-ranging" free trade agreement with the UK.

But one section reignited the row on fishing rights, which burst forth earlier this week when the UK Government came under fire for agreeing to stick to the rules of the Common Fisheries Policy until December 2020 rather than March 2019 as had originally been suggested.

At the December 2019 fisheries council, which will set quotas for the following 12 months, the UK will not be a decision-maker but will instead be consulted. However, it does have the guarantee that its own quota will not be reduced in that period.

Mrs May held a private meeting with Scottish Tory MPs - enraged by what was dubbed a “betrayal” and a “sell-out” of the country’s fishing communities - assuring them there would be no future trade-off.

However, in its trade negotiation guidelines published on Friday the EU27 says: “In the overall context of the Free Trade Agreement, existing reciprocal access to fishing waters and resources should be maintained.”

Mike Hookem the Ukip MEP accused the EU of “holding Britain’s fishing grounds hostage" in the Brexit talks.

He said: “Any move to allow the EU to continue stripping the UK’s rich fishing resources after 2020 will be the completion of a betrayal that started with Edward Heath in 1972, continued when the Tories allowed fishing to be included in the transitional arrangements and will end with continued access post-2020.”

David Duguid, the Conservative MP for Banff and Buchan, insisted there must be no deal, which guaranteed the EU any specific share of access to UK waters.

“The Prime Minister, in her Mansion House Speech, committed that British fishermen will have a fairer allocation to our waters than they do now but this must not be traded away as part of a trade deal. Access and trade must be kept separate,” insisted the Tory MP.

Michael Russell, the Scottish Government’s Brexit spokesman, noted even the basic trade deal the EU27 was offering would be “dependent on maintaining current rules for the fishing industry”.

He asked: “Is it all pain for no gain?” adding: “The Scottish fishing industry is facing a massive sell-out because of the total failure by the UK to keep its promises to them.”

His Nationalist colleague, MSP Stewart Stevenson noted: “Despite their bluster, it's clear that the Scottish Tories will end up selling out the fishing industry once again."

Bertie Armstrong of the Scottish Fishermen’s Federation insisted the EU’s fishing wish-list did not fit with international law. “They can think again; it’s just not acceptable,” he declared.

“The EU’s statement is absurd. There is no connection between trade and access to waters. International law does not allow it. We have made that clear to our government,” added Mr Armstrong.

After the transitional deal was ratified at the European Council, the PM said she felt there was now "a new dynamic" in the negotiations.

"We are approaching this with a spirit of co-operation, a spirit of opportunity for the future as well, and we will now be sitting down and determining those workable solutions for Northern Ireland but also for our future security partnership and economic partnership," said Mrs May.

The EU document:

*envisages "ambitious provisions on movement of natural persons based on full reciprocity and non-discrimination among member states";

*calls for the EU to have "as close as possible a partnership" with the UK in future, covering trade, security and economic co-operation;

*warns the UK pulling Britain out of the single market and customs union will "limit the depth" of any future partnership and "inevitably" lead to frictions in trade, resulting in "negative economic consequences, in particular in the United Kingdom".

Michel Barnier, the EU’s chief negotiator, kissed Mrs May's hand as they met in the Europa building in Brussels and said later that Friday marked a "decisive" moment in "this difficult and extraordinary negotiation".