More than 70 officers were involved in a major operation to tackle suspected modern slavery at three county sites, including one near Desborough.
Pre-dawn raids were carried out at three Travellers’ sites, at Justin Park near Market Harborough, Greenfields in Braybrooke and at Lower Ecton Lane in Northampton.
Five foreign nationals, four Romanians and one Pole, were located at the Greenfields site and they have been safeguarded by Northamptonshire Police, working alongside colleagues from the National Crime Agency.
The safeguarded men were all located at the Greenfields site.
Officers there discovered three caravans at the location.
A total of three men, aged 33, 29 and 20, as well as a 23-year-old woman, were arrested on suspicion of offences committed under the Modern Slavery Act 2015.
The woman and the 33-year-old man were held at Justin Park while the other two men were arrested at Greenfields.
A 22-year-old man was also arrested at Justin Park on suspicion of burglary offences allegedly committed in Leicestershire.
They are all currently being held in custody in Kettering.
In the third part of a rolling operation, officers later safeguarded a British national at the Lower Ecton Lane site.
They also arrested a 76-year-old man and a 73-year-old woman on suspicion of modern slavery offences.
Another man wanted on suspicion of modern slavery offences was also arrested following an ANPR hit elsewhere in the county.
They are being held in custody in Northampton.
Det Chief Supt Kate Meynell, head of crime, public protection and intelligence, said it had been an extremely successful operation.
She said: “Our primary aim today was to safeguard individuals who we strongly suspected were being used as modern day slaves and made to live in extremely poor conditions.
“Modern slavery takes many forms and in this case it is labour exploitation with victims made to work extremely long hours for minimal pay.
“They receive no training, pay no taxes or insurance and remain extremely vulnerable.
“With the support of colleagues from the National Crime Agency, who have great experience dealing with this emerging threat, we executed a fast-moving operation today which has protected those very vulnerable people from harm and resulted in the arrests of at least four people.
“Northamptonshire Police treats modern slavery extremely seriously and operations such as this send out a clear message to those involved in labour exploitation that we will find you.”
James Behan, from the NCA’s Modern Slavery and Human Trafficking Unit, said: “Modern slavery is a priority across law enforcement, and our involvement in operations such as this have shown us that it affects all types of communities across every part of the UK.
“It can be difficult to spot because often the victims don’t even know they are being exploited, but there will be people living and working where victims come into contact with everyone else’s so-called normal lives.
“They may see something they feel is not quite right.
“That might be someone seeming afraid, vulnerable or being controlled, moved around or forced to work against their will.
“If they do, we need the public to speak to us.
“Anyone with suspicions can call their local police force on 101 or the Modern Slavery Helpline 08000 121700.”
The term ‘modern slavery’ includes the offences of human trafficking, slavery, servitude and forced or compulsory labour, including sexual or criminal exploitation.
Today’s operation was also supported by staff from the Gangmasters and Labour Abuse Authority and Northamptonshire Fire and Rescue Service with additional assistance from the RSPCA.