'What more can be done to improve their response to this terrible crime?'
Cambridgeshire Constabulary Police has recorded dozens of cases of modern slavery in recent years, figures reveal.
A recent parliamentary report on modern slavery concluded that the practice “pervades every community" in the UK, and warned the number of victims could be in the tens or even hundreds of thousands.
Modern slavery was introduced as a single, specific offence under the Modern Slavery Act, which came into effect in March 2015.
Since then, Cambridgeshire Constabulary Police has recorded 87 instances, according to Home Office data up to the end of December last year.
Examples of modern slavery include domestic servitude, forced sex work, or labour exploitation in industries such as agriculture, or in businesses like nail salons and car washes.
It can also involve criminal exploitation, such as in cases where children or vulnerable adults are recruited into the drugs trade.
Experts have warned that a lack of support for victims could be hindering investigations, after the rate of offenders being charged fell to a record low.
In Cambridgeshire, while the number of cases has grown since 2015, while the proportion resulting in an offender being charged has fallen year on year.
Officers carried out 31 investigations into slavery offences in 2018, 24 of which had been concluded by the time the data was released.
Of these, none resulted in charges being brought.
Difficulty gathering evidence was cited as the reason for not bringing charges in 46 per cent of cases – 25 per cent where the victim didn't support further action being taken, and 21 per cent where they did.
Police closed the case without identifying a suspect in 46 per cent of cases.
In comparison, a suspect was charged in nine of the 20 cases investigated and concluded in April to December 2015 – a rate of 45 per cent.
Police forces across England and Wales have recorded over 10,000 slavery offences since 2015 – almost half of them in 2018 alone.
In 2018, just 3 per cent of concluded cases ended in charges being brought, compared to 19 per cent in 2015.
The Human Trafficking Foundation said modern slavery cases were some of the most complex police may ever have to deal with, involving highly vulnerable and traumatised victims who may not want to help the police.
However, a spokesman said it was disappointing the increase in the number of victims being identified hadn’t led to large increase in prosecutions or convictions.
“The lack of support and stability we provide victims is no doubt partly to blame for these low figures,” she said.
“Survivors of any serious crime would struggle to be able to trust authorities if they live in unstable accommodation with barely anything to live on, and do not know where they will be housed in a month or whether they will be made to return to a place that they know could lead to re-exploitation.
She added that giving victims more incentives, such as the right to remain in the UK, would encourage more to help police "put their traffickers behind bars".
A spokesman for the Crown Prosecution Service said when police did charge a suspect, they prosecuted 67 per cent of them.
The Home Office said the Government was committed to stamping out the "abhorrent" crime.
“Our world-leading Modern Slavery Act has led to thousands of victims being protected and hundreds of convictions," said a spokesman.
"But we know there is more to do and are working with police to see what more can be done to improve their response to this terrible crime.”