Rapists and killers are among hundreds of foreign criminals who have dropped off the Home Office’s radar.
Immigration authorities also lost track of overseas nationals convicted of kidnap, weapons possession and robbery.
They had been living in the community while facing removal from the UK.
Figures obtained by the Press Association show 450 foreign national offenders (FNOs) absconded in two and a half years to the end of June.
Some were later located but the whereabouts of more than 200 were unknown up to two years after contact with officials ceased.
Conservative MP Tim Loughton, a member of the Commons Home Affairs Committee, described the findings as “horrifying”.
He said: “These are very concerning figures and confirm a worrying trend that we are a soft touch when it comes to dealing with foreign national offenders.
“It is a mystery to me why we do not immediately deport these criminals, some of them highly dangerous, back to their country of origin, and let their authorities deal with them.
“The fact that these people are escaping the watchful eye of the Home Office and are back on our streets is horrifying.
“Innocent people going about their daily lives could be at risk.
“Foreign criminals that have not been deported for breaking the laws of our country are now wandering around our streets.
“We need to be pulling out all the stops and booting them out of our country ASAP for having abused our hospitality and generosity.”
If there is no immediate prospect of deportation or removal, convicted foreign nationals who have completed their sentence can be managed in the community.
They are required to report to officials at set times and can be subject to bail conditions and electronic monitoring.
Offenders are recorded as having absconded if their whereabouts are unknown and all procedures to re-establish contact have failed.
Figures obtained under Freedom of Information rules show 251 FNOs absconded in 2016, followed by 164 last year and 35 in the first six months of this year.
As of the end of June, 223 male FNOs had not been found.
Eleven females who absconded in 2016, plus unspecified numbers of five or fewer who absconded in 2017 and January to June this year, were also yet to be tracked down.
Offenders convicted of murder, manslaughter, rape, kidnap, weapons possession, robbery, conspiracy to defraud, theft, burglary and death by dangerous driving were among those unaccounted for.
Exact figures are not known for most offence categories, including murder, manslaughter and rape, as Home Office policy means it does not disclose data where the number is five or less, so individuals’ identities can be protected.
The department also refused to provide details of the nationalities of absconders on the basis that disclosure could hamper efforts to deport or remove FNOs by undermining border controls and agreements with other countries.
Where statistics were given, they showed nine offenders previously convicted of violent crimes were yet to be located in June after absconding in 2016.
Eighty-two individuals with convictions for drug-related offences were also yet to be found.
The Home Office said some of the absconders recorded as unfound in June may have been traced since.
Shortcomings in arrangements for keeping track of foreign criminals living in the community were flagged up in a report from the immigration watchdog last year.
It found offenders can fail to attend meetings with staff on as many as 19 occasions before the alarm is raised, while planned removals were often frustrated by last-minute legal challenges.
Many absconders are traced at overseas locations and can be prevented from returning to the UK, officials said.
They added that it is likely others have also left the country, and will be denied re-entry if they try to return.
A Home Office spokeswoman said: “We always seek to deport those who commit crimes and whose conduct poses a serious threat to the basic fundamentals of society.
“We never give up trying to locate absconders, which is why we have introduced measures in the Immigration Act 2016 that will mean that in the future all non-detained foreign nationals subject to deportation proceedings or a deportation order will be considered for electronic monitoring.
“We have removed more than 44,500 foreign national offenders since 2010, and this week, like every week, more than 100 foreign criminals will be removed from the UK.
“In 2017-18, we removed more than 2,000 FNOs direct from prison under the Early Removal Scheme.”
A national team has traced more than 2,000 absconders since it was established in 2009, the department added.