The European Commission is investigating the sharp rise in detention and deportation of EU citizens from the UK since the Brexit vote amid concerns the Government may be acting unlawfully.

Deportations are at their highest since records began, with 5,301 EU nationals removed during the year ending June 2017, an increase of 20 per cent on the previous 12 months, although the number has risen steadily since the Conservatives came to power in 2010.

Critics have claimed the Home Office is deliberately targeting EU nationals as part of a post-Brexit crackdown to show the Government is serious about bringing down immigration.

Brexit: the deciders Show all 8 1 /8 Brexit: the deciders Brexit: the deciders European Union's chief Brexit negotiator, Michel Barnier Getty Brexit: the deciders French President Emmanuel Macron Getty Brexit: the deciders German Chancellor Angela Merkel Reuters Brexit: the deciders Commission President Jean-Claude Juncker EPA Brexit: the deciders The European Parliament's chief Brexit negotiator Guy Verhofstadt Getty Brexit: the deciders Britain's Prime Minister Theresa May Getty Images Brexit: the deciders Britain's Chancellor of the Exchequer, Philip Hammond PA Brexit: the deciders After the first and second appointed Brexit secretaries resigned (David Davis and Dominic Raab respectively), Stephen Barclay is currently heading up the position PA

The Government claims it only targets those who it believes should not be in the country because they have criminal convictions or otherwise pose a threat.

The Observer reports that a leaked email reveals the EU’s Brexit negotiating team referred a complaint concerning the detention of EU nationals in the UK to the Commission.

The complaint, made by the charity Bail for Immigration Detainees (BiD), is being looked into by the directorate general for justice and consumers, whose brief is to ensure the EU is “an area of freedom, security and justice”.

Celia Clarke, director of BiD, told the paper: “If other European countries were targeting British expats in this way, there would be justified outrage.”

The charity claims EU citizens are sometimes being detained and deported for relatively minor offences including driving offences. There have also been a number of cases where EU nationals have been detained despite having committed no crime at all, sometimes because they have mental health problems or are sleeping rough.

EU directives state it is illegal for member states to expel EU citizens “except on serious grounds of public policy or public security”.

The Government has repeatedly been accused of using EU nationals as bargaining chips in the Brexit negotiations because of her refusal to guarantee their status in the country.

Ms May’s offer to write legal protections for EU citizens living in the UK into the exit deal is not enough to convince Ms Clarke, who said: ““The warm sentiments expressed in the Prime Minister’s Florence speech are at odds with the actions of Home Office officials, who appear to be riding roughshod over EU citizens’ rights to free movement,” said Clarke.

“The Government has a callous disregard for EU nationals’ rights to live and work in the UK.”

A Home Office spokesperson said: “We have toughened our response to foreign nationals who abuse our hospitality by committing crimes in the UK.