LONDON – The Home Office accidentally threatened to deport 100 European citizens from the UK despite having no legal grounds to do so.

The department sent threatening deportation letters to a variety of EU nationals last week, telling them that they had a month to get out or face forcible deportation.

After being challenged on the threat officials admitted that the messages were sent in error and told recipients to disregard them.

One European who was sent the letter, Finnish academic Eva Johanna Holmberg, said she was sent a letter on Thursday warning her to leave or face punishment.

Holmberg lives in Brighton and is a visiting history fellow at Queen Mary, University of London.

The letter, which she posted on Twitter, told her to expect "administrative removal" and that she was "liable to be detained."

As an EU citizen, Holmberg has an unqualified right to live and work in the United Kingdom, the same as any British citizen.

The situation could change after the UK leaves the European Union, but no specifics have been announced.

Earlier this year, Brexit secretary David Davis said that EU citizens currently living in the UK would not be deported, describing the idea as "frankly incredible."

In a statement to Business Insider, the Home Office described the 100 people affected as "a limited number" and said they were urgently investigating how the mistake was made.

A spokesman said: "A limited number of letters were issued in error and we have been urgently looking into why this happened. We are contacting everyone who received this letter to clarify that they can disregard it.

"We are absolutely clear that the rights of EU nationals living in the UK remain unchanged."