THE 16-year-old boy looked terrified as police ordered him to empty his pockets.

Dressed in filthy clothes, not washed for weeks, the teenager was arrested and taken away.

It was October 2006, and I was covering an eviction at the Hovefields camp. Something told me this vulnerable-looking teenager wasn't a traveller.

In previous months, a number of contacts who know the long-standing English gipsies in Basildon, had mentioned "dossers" or "slaves" used by certain travellers.

Rumour was they included homeless vagrants, and more recently illegal immigrants, employed by some travellers, cash in hand, as labourers, dogsbodies and even criminals, ready to take the rap for their "boss".

I had no idea they existed and had seen no evidence.

But when the boy stepped out of the grubby mobile home that October, my reporter's instinct told me I was seeing my first "dosser".

The squalid home, which was about to be demolished, was a cast-off earlier abandoned by a traveller family.

It was ramshackle and dirty ,with broken windows and had a burned-out lorry in the yard.

There was an outhouse for washing, but no sink. Most travellers pride themselves on the cleanliness of their mobile homes and caravans and all those I had been in have been squeaky clean.

I explored the back of this mobile ome. Used syringes, beer and strong white cider bottles, rubbish and hardcore porn DVDs littered the ground.

Police seemed reluctant to discuss who the boy was, but confirmed he was a 16-year-old runaway from Brighton, who was not a traveller, but had been living in the mobile home.

He was arrested on suspicion of stealing a mobile phone and DVD player found inside, but later released without charge.

They said an older man, in his forties, also living in the mobile home, fled when they arrested the boy. It is believed he was a dosser too.

This bizarre scene of squalor, drugs and pornography contrasted starkly with the family values in keeping with the legal Irish travellers living on the plot next door.

Bernadette Doran, 34, and husband Patrick, 35, got four years temporary permission to stay there in 2006, after leaving a council house in Church Road, Acton, West London.

A crowd formed at the Dorans' plot where a new brick wall was being built by two men.

My reporter's instinct again kicked in and told me I could be looking at more of these so-called dossers.

The hunch was right. The Echo has since learned at least one of these men is still living unofficially on the site.

It was the shocking sight of that teenager, and the other dossers, which sparked this 18-month investigation into modern-day slavery on traveller sites in Basildon.