One out of every five killers is an immigrant. Up to a fifth of killers in England and Wales are foreign, police figures released in 2009 suggest. Out of 371 individuals accused or convicted of murder or manslaughter last year, 79 were from abroad - more than 21 per cent.
Foreign immigrants make up only around a tenth of the UK population, meaning they are statistically twice as likely as native Britons to be charged with or found guilty of an illegal killing.
In London, almost 40 per cent of those in such cases in the past year were from overseas, or of unknown origin.
Opposition critics said the findings reflected the Government's failure to deport foreign criminals, and the ease with which offenders from abroad can slip through border controls.
The most common nationality for foreigners involved in murder and manslaughter cases was Polish, followed by Nepalese, Lithuanian, Somalian and Sri Lankan.
Around half the police forces across England and Wales provided data under the Freedom of Information Act, revealing strong regional differences.
The highest figures were in London where in the year to April 2009, 93 of the 233 people accused or convicted of murder and manslaughter were either non-British or from unknown backgrounds.
In West Mercia, five out of 22 were foreigners - 23 per cent - from Lithuania, Poland, and the Republic of Ireland. Nottinghamshire showed the same proportion, with three out of 13 cases.
But some forces - including Cheshire, Humberside, Hampshire, and Merseyside - recorded no cases with foreign killers. The figures may be an underestimate as 11 out 30 forces which responded claimed they did not record nationalities of either killers or murder victims, and others had gaps in the information.
As foreign suspects are typically harder to identify and trace, meaning that crimes are less likely to be solved, the real proportion could be significantly higher.
The figures showed foreigners were also more likely to be victims of murder or manslaughter, accounting for 20 per cent of all those killed in England and Wales in 2007-8, and 13 per cent last year.
Shadow home secretary Chris Grayling said: 'The Government seem to have completely failed to get to grips with foreign nationals' crime in the UK.
'These figures underline the scale of the problem, but we know the Government are simply failing to deport offenders in the way they should be.'
Detective Chief Inspector Murray Duffin, of the Scotland Yard Extradition and Intelligence Unit, warn: 'Britain is becoming a magnet for increasing numbers of criminals from the former Eastern block countries which are now members of the EU.'