Creating new identities, the criminals, many wanted for serious offences, are able to get away.
But the net is now closing in on those offenders. In six years, 500 suspected criminals living in the West Midlands were deported to face charges in other countries.
Many of those offenders, including alleged killers and fraudsters, have been stopped under joint-border police initiatives. They include Operation Trivium.
The operation, now in its ninth term, is taking place this week with a focus on areas including Coventry, Birmingham and Wolverhampton.
It hunts out gets people human trafficking, modern day slavery, illegal immigration and a wide range of other crimes.
Co-ordinated by a specially multi-national set-up control room at Tally Ho Conference Centre in Birmingham, police officers on the ground target criminals.
And a special European Operations Control Centre, based at Europol headquarters in The Hague, with officers from TISPOL, the European traffic police network, carries out checks on suspects picked up.
The participating countries are Ireland, Spain, Lithuania, Romania and the Netherlands.
Teams of officers on the ground use ANPR cameras on vehicles to initially pick up vehicles with no tax, no licence or connected to an offence.
Once at a check point, the car is then checked again with the control room.
It aids police officers to pick up on people’s backgrounds which otherwise would not appear on the UK police data checks. Speaking from a check point at Dunstall Park in Wolverhampton, Insp Sion Hathaway, from the Central Motorway Police Group said: “Within Europe it is fairly easy to cross borders.
“People are allowed and encouraged to cross country borders, then there is an issue in that there is a certain criminal minority that have taken advantage of that to create new lives, create new identities, so people wanted for serious offences in their home countries can slip under the radar.
“And for checks in this country we normally do not have access to the European wide system, but the difference is, when we stop those individuals during Trivium week, we have got access to their systems instantaneously, we can contact our officers and it is really effective.
“These people can be wanted for some really serious offences. We have can pick up that criminal, it stops them inflicting further crimes in communities.” Operation Trivium runs for a week, focusing on a different town or city every day.
In Wolverhampton, the team of officers are briefed before heading out in the city.
Each car has two ANPR cameras fitted on its roof, checking the details of every passing car.
That information is relayed quickly to the officer’s dashboard, with an alert sounded when a suspect car goes by.
The screen tells the officer the car make, model, registered motorists, date of birth and address. It will also flag up if there is no insurance or tax, or if the registered motorist is wanted for an offence.
While some cars will sit in lay-bys picking up every car going by, others will patrol certain areas where foreign criminals are believed to be operating. Bushbury, Whitmore Reans and Dunstall Park were among the areas. From 2010 to last year, 495 suspected criminals were extradited from the West Midlands under the European Arrest Warrant.
West Mercia Police deported 72 suspects and extradited five back to the UK, while 62 suspects were arrested in Staffordshire, with the county’s force extraditing 24. Over the same period 54 suspects were snared in Europe and brought back to the West Midlands, including some of Britain’s most-wanted fugitives.
It is unclear what impact leaving the EU will have on UK police forces remaining part of TISPOL and having the ability to use the European Arrest Warrant.
But, of course, initiatives such as Operation Trivium does not only pick up foreign criminals.
While the operation is being carried out in Wolverhampton, a man wanted for an assault in the city is arrested and a car pursuit leads to an abandoned car, which is then seized.
TISPOL Superintendent Paul Keasey said: “We have a range of effective tactics to ensure that Trivium 9 makes a big contribution to safer, more secure roads, and in particular to protecting the most vulnerable members of society.”