Five people arrested in Bedfordshire under suspicion of forcing 24 men to work in 'filthy and cramped' conditions

Twenty-four men believed to have been held against their will and forced to work have been freed from a caravan site in Bedfordshire.

Five people on the site, in Leighton Buzzard, have been arrested under suspicion of keeping 24 men from England, Romania and Poland as slaves in "filthy and cramped" conditions, police said. Four men and a woman were arrested after a long-running investigation by Bedfordshire police.

Officers believe a number of people were being held against their will – some for as long as 15 years – and being forced to live in squalid conditions and work for no pay at the Greenacre caravan site.

More than 200 officers raided the site at 5.30am on Sunday, releasing the 24 men, who were taken to a medical centre.

Dog-handling officers, helicopter and firearms support units were on hand to execute search warrants. The four arrests were made under section 71 of the Coroners and Justice Act, and the suspects held at police stations across Bedfordshire and Hertfordshire.

Weapons, drugs and money were also found at the site, police said.

Detective Chief Inspector Sean O'Neil, of the Bedfordshire and Hertfordshire major crime unit, said: "The men we found at the site were in a poor state of physical health and the conditions they were living in were shockingly filthy and cramped.

"We believe that some of them had been living and working there in a state of virtual slavery, some for just a few weeks and others for up to 15 years."

Police, who were assisted by officers from the UK Human Trafficking Centre – also apologised to residents of the site who were not believed to be involved in the crime. "Because of the number of victims and suspects and the size of the site, we needed the assistance of many officers from specialist units today," O'Neil said.

"We are aware the operation has caused a lot of disruption to the other residents of the site and we thank them for their co-operation and understanding.

"A small number of officers are remaining at the site to complete searches and to liaise with the residents. The offences that are being investigated are extremely serious."

• This article was amended on 12 September 2011. The original said that the four arrests were made under the Slavery and Servitude Act 2010. This has been corrected.