The UK's divorce from the European Union came into effect on 31 January 2020.
The European Court of Justice on Thursday confirmed definitively that UK citizens lost their EU rights as a result of the 2016 Brexit referendum.
The Court was ruling on three legal challenges on appeal after they were first rejected by the General Court of Justice.
The three cases had been brought forward by UK nationals residing in the UK and EU member states who demanded that the court annul or partly annul the January 2020 decision by the Council of the EU to approve the Withdrawal Agreement.
They claimed that the treaty and the Council's backing of it had deprived them of the rights they had exercised and acquired as EU citizens.
But, like the General Court before it, the Court of Justice ruled that the loss of EU rights is an "automatic consequence of the sole sovereign decision taken by the United Kingdom to withdraw from the European Union, and not of the withdrawal agreement or the Council's decision."
"The Court concludes that the British citizens do not have an interest in bringing proceedings and that the General Court rightly rejected their actions as inadmissible," it added.