Migrant victims of crime are being handed over to immigration enforcement officials by police when they report crimes, figures show.

Of 45 police forces asked about the practice of handing over victims’ details, more than half said they did, three said they did not, while the rest either did not reply, did not give a clear yes or no, or said they did not have information about it. The forces were responding to freedom of information requests put to them by BBC Two’s Victoria Derbyshire programme.

There are fears the disclosure could discourage migrant victims of crime from coming forward, although the Home Office said it would support vulnerable migrants “regardless of their immigration status”.

“Victims of crime must be treated first and foremost as victims,” a spokesperson said.

The National Police Chiefs’ Council (NPCC) Lead for Immigration Crime, Chief Constable Shaun Sawyer, said: “We are considering whether further advice to police forces is required.”

He went on: “The police priority is to protect victims and investigate crime, and we are extremely careful about doing anything to deter victims from reporting to us. Each case is considered very carefully but there will be instances where police need to exchange information with the Home Office.”

The NPCC issued guidance on the treatment of victims of crime with outstanding immigration issues in December, saying they would not be arrested on the basis of their immigration status unless there was “an immediate risk of harm to a specific individual”. But just three police forces who responded to the FoI requests were adhering to this guidance.

Police officers are able to hand some victims of crime over to immigration enforcement because they have free rein to make background checks on them on the police national computer (PNC).

Police forces have told the Guardian they use their discretion when making these checks on both British people and foreign nationals who report crimes to them. Victims of crime are not aware police are making the checks, nor do police need their permission.

The Guardian previously reported that Miroslaw Zieba, a Polish national who had committed criminal offences in his home country, reported being the victim of an assault to police who handed him over to Home Office officials after making a PNC check. He was then arrested and detained.

Fahad Ansari, Zieba’s solicitor, said: “This creates a real danger that the decision whether to check the PNC for a victim of crime will be subject to an individual officer’s own prejudices. In other words it will lead to the profiling of victims of crime, which will only further reduce public confidence in the police.”

Martha Spurrier, the director of the civil liberties organisation Liberty, expressed concern about these discretionary checks. She said: “The government’s obsession with making the UK a hostile place for foreign people at any human cost has put border controls in our hospitals, our schools and our banks – but targeting victims of crime is a new low. Police are bound by the Human Rights Act to investigate crimes effectively, regardless of who the victim is – but this gives officers a licence to act on their prejudices with no guidance, oversight or accountability.

“It will leave people afraid to report crime, robbing them of protection under the law and creating impunity for criminals who target vulnerable people with unsettled immigration status. This is criminalising victims and letting criminals off the hook.”

Essex police said it was “standard procedure” to check the PNC when investigating reports of crime from victims. The Metropolitan police said PNC checks on victims of crime were conducted at the discretion of officers and West Midlands police said checks might be carried out if a person reporting a crime was known to them.

Greater Manchester police declined to answer and said it was a policy matter for the NPCC. Police Scotland said it did not routinely carry out such checks but it was an available option. The Police Service of Northern Ireland said it may look up 999 or 101 callers on the PNC when they call to report a crime.