More than 200 officers raided a caravan site yesterday to rescue a group of men allegedly being held as slaves and forced to live in squalid conditions – some for as long as 15 years.

Four men and one woman, all residents of the site, were arrested on suspicion of slavery offences at the Greenacres travellers’ site in Leighton Buzzard following the early-morning operation, Bedfordshire Police said.

The arrests come as a result of a long-running investigation by the force which suggested 24 men were being held against their will in poor conditions at the site, and forced to work for no pay.

The officers arrived at the site at 5.30 a.m. yesterday.

The 24 men, all believed to be victims of slavery, were taken from the site to a medical centre. Police said they were mostly from English and eastern European backgrounds.

The five people were arrested using new legislation under the Slavery and Servitude Act 2010 and are being currently held at police stations across Bedfordshire and Hertfordshire, police said.

Dozens of police vans remained at the site, which consists of a series of gated properties set off a winding road, until late afternoon.

A few young children played in the road running through the campsite but many residents were unwilling to speak about what had taken place this morning.

Detective Chief Inspector Sean O’Neil, from 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.

“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. 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.”