A Hungarian man whose dangerous driving killed a British father has been allowed to remain in Britain thanks to European Union rules.
The man, who was jailed for four and a half years for the crime in 2011, had been told by the Home Office that he would be deported on his release from prison.
But he lodged an appeal and immigration judges ruled he could not be removed.
They said European Union rules only allow citizens of member states to be deported if they pose a “genuine, present” threat.
The case will trigger further concerns about Britain’s ability to control its borders amid growing criticism of EU freedom of movement rules.
David Cameron, the Prime Minister, has signalled his determination to introduce tough new restrictions to stem the flow of EU citizens to Britain.
Amid growing calls for Britain to leave the EU, or significantly alter the terms of our membership, the Prime Minister insisted he ruled "nothing out" if British demands for change fall on deaf ears.
In the latest case, the Hungarian man – who can be identified only by the initials AZ after being granted anonymity by the court – killed the father after driving in a “reckless, foolish and irresponsible” manner.
The victim, whose identity was also kept secret by the court, was married and his mother had previously lost another son in tragic circumstances, the court heard.
AZ was jailed for four and a half years and banned from driving for five years.
European regulations say any criminal from another EU state must pose a “genuine, present and sufficiently serious threat” to be deported.
When AZ brought his appeal to the first-tier Immigration and Asylum Chamber, the judges said his case was not serious enough to justify deportation.
The Home Office later appealed to the upper tribunal but dropped the case just before it was, in any effect, upheld by senior judges.
A Home Office spokesman said: "We are disappointed by this judgment.
"We firmly believe that foreign nationals who commit crimes in the UK should be deported and we take action to make that happen.
"Last year, we removed more than 5,000 foreign criminals, the highest number since 2010/11, and we have removed more than 22,000 since 2010”.