(MF/AFP/JB) The door will not close on the 500 or so British civil servants working within the European Institutions in Luxembourg, Commission President Jean-Claude Juncker has announced.

The message, published on the website of EU civil servants' union the USL, may provide some reassurance to the local workers following last week's referendum in which a slim majority voted for the UK to leave the European Union.

"Personally very saddened" by the vote, Jean-Claude Juncker addressed the British EU officials, acknowledging that "this vote is a source of concern for your future”.

“According to your status, you are servants of the Union. You work for Europe. You left your national hats at the door when you joined this institution. Now that door will not close on you,” he wrote.

ULS President Miguel Vicente Nuñez added his voice to show solidarity with the plight of the Britons working for the European Institutions, who face uncertainty in their careers. He stressed the commitment of the institutions to treat British civil servants the same as those of any other nationality.

Juncker, for his part, has promised to “work with the presidents of the other European Institutions to ensure that we can continue to benefit from your remarkable talent, experience and engagement”.

Will these messages be enough to reassure the British civil servants working within European Union institutions?

According to Article 49 in the work code of EU civil servants, civil servants may be required to resign from office if they cease to fulfil the conditions laid out in Article 28 a, which states: “no official may be appointed if he is not a national of a Member State, unless waived by the authority vested with power of appointment.”

Such powers have been invoked several times in the past: to Danes before the accession of Denmark to the EU and there are Norwegian civil servants even though Oslo is not part of the EU28.

According to official figures, 1,164 Britons are working as civil servants within the European Commission, representing 3.5 percent of the total 32,966 European civil servants.

If they were to be retained, London would certainly be expected to pay for their pensions, suggested Félix Géradon, Assistant General Secretary of the Brussels Union said.