The European Union’s chief negotiator in the Brexit talks is insisting the European Court of Justice (ECJ) should not only continue to have jurisdiction over EU migrants in Brexit Britain but that it should also retain its current powers to fine the British government.

Frenchman Michel Barnier believes the ECJ should be able to demand “a lump sum or a penalty payment” from Britain if it should break a yet-to-be-confirmed deal on EU nationals’ rights after Brexit.

“The withdrawal agreement should provide for an effective mechanism to ensure compliance by the parties with judgments of the Court of Justice handed down in accordance with the withdrawal agreement,” reads a position paper seen by The Guardian newspaper.

The EU are behaving like gangsters. They're treating Britain like a hostage when in fact we're now free. pic.twitter.com/K0CRjNbtqj — Nigel Farage (@Nigel_Farage) April 5, 2017

Critics have compared Barnier’s demand for the ECJ to enforce EU nationals’ rights in Britain after Brexit to David Davis demanding that British courts should enforce British nationals’ rights in the EU after Brexit.

Leave Means Leave co-chairman Richard Tice said the demand was a clear indication that “the EU is in denial” about Britain’s departure.

“As soon as Britain leaves the EU we are no longer subject to the meddling ECJ,” he asserted.

“The British Government must make it absolutely clear to the EU that this is the case.”

Liam Fox – "We voted to have control of our laws, borders and money. That means not being under the influence of the ECJ." #Brexit pic.twitter.com/WEJ2BWsGdh — thebrexiteer (@BrexiteerGB) June 30, 2017

Responding to Barnier on the BBC’s Question Time programme, International Trade Secretary Liam Fox confirmed: “In the referendum, we voted to have control of our own laws, control of our borders, and control of our money; that means not being under the influence of the European Court of Justice [and] not having complete Free Movement as we have inside the Single Market.”

Long-time Brexit supporter Jacob Rees-Mogg was more pointed, saying: “The idea that a foreign court should rule on the rights of people living [in the United Kingdom] is akin to the outdated colonial approach taken towards China in the unequal treaties of the 19th century.”