With hundreds of mobile homes strewn haphazardly along a maze of dirt tracks, Buckles Lane feels more Wild West than 21st-century Britain.

The site in rural Essex was set up in 1980 as winter accommodation for travelling showmen, but it has since ballooned beyond 31 authorised pitches to more than a hundred.

It is now the biggest traveller camp in Europe with more than 835 static caravans and 1,000 occupants, over two-thirds of whom – according to a council report - are not meant to be living there.

Until recently they included Thomas McKenna, who was jailed in January for using a caravan as the base for an underworld weapons workshop.

The 60-year-old lorry driver was found with six pistols, a shotgun, a replica assault rifle and the component parts of a Sten Mark II submachine gun. He was stockpiling the weapons for a 'race war' against Muslims - at the same time as supplying criminal gangs.

While the case represents a rare victory in efforts to impose some kind of order over the anarchic mess that is Buckles Farm, the task is far from over.

Rental accommodation in static homes is being advertised for as little as £120 a week on Rightmove, Gumtree and Facebook, with several ads listing 'working men' as the target market. 

Insiders say the cheap rents and lack of formal ID requirements have attracted illegal migrants, who are living at the site while working local cash-in-hand jobs. 

But Buckles Lane is far from the only place where this is happening. 

The Daily Mail can reveal evidence of illegal migrants being housed at other traveller sites in Essex and elsewhere in England. And if the prospect of immigration laws being shamelessly flouted wasn't bad enough, the reality may be darker still... 

Last May, a group of 30 Conservative MPs wrote to the Home Secretary to complain that travellers were buying 'rural or greenfield' plots in their areas before illegally converting them into permanent sites offering caravans to rent.

The MPs, representing constituencies across southern England, the West Midlands and North Yorkshire, said police and council investigations had identified many of the tenants as 'undocumented migrants, some of whom are working illegally in the gig economy'.

The issue has caught the attention of Immigration Enforcement, with a raid at Green Lane caravan park in Surrey on May 20 last year leading to nine arrests.

The suspects - who included six Brazilians and three Indians - were accused of substituting for delivery riders and completing food deliveries on their behalf without the right to work in the UK. 

Six of them have now been deported, with the remaining three on immigration bail. 

On March 13, a second raid on a traveller site in Bromley found a further 18 people from Brazil, Poland and the Czech Republic who had also been illegally working as delivery drivers.

Eight have been detained pending their removal from the UK and the other ten have been placed on immigration bail pending further inquiries.

The Home Office says it has ramped up the number of raids and removed nearly 60,000 illegal migrants since the general election. 

While the use of traveller sites as off-the-books accommodation for illegal migrants is a cause of concern, they are also feared to be hiding an even more serious problem.

Modern slavery, which involves people being forced to work for no or very little money, has been an issue at traveller sites for decades.

The most notorious case involved the Rooney family, who were jailed in 2017 for a total of 79 years for using 18 homeless men as slave labourers for their driveway and tarmacking business.

The family, from Lincolnshire, amassed a £4million fortune while imprisoning their victims in stinking, filthy caravans and using drugs, alcohol and threats of violence to keep them under 'total control'.

A separate case from 2019 saw 60-year-old traveller Michael Joyce handed a five-year prison sentence for forcing two heroin addicts to build him a pub at Redbridge Hollow in Oxford.

A trial heard how Joyce used Paul West and Paul Gilding as slave labourers for more than two years, 'terrifying' them into submission with regular beatings and only ever 'paying' them with cannabis or cigarettes.

Another traveller family, the Connors, kept slave labourers at sites in Gloucestershire, Leicestershire and Nottinghamshire – with a police raid in 2011 finding shaven-headed men living in squalid conditions, their clothes covered in excrement. 

The victims in these cases were British nationals, but are illegal migrants - who are particularly vulnerable to labour exploitation - also being targeted?

Concerning claims are now being made about one site in particular - Hovefields, near Wickford in Essex.

A smaller neighbour to Dale Farm, a notorious site cleared in a mass eviction in 2011, Hovefields has been at the centre of modern slavery allegations for nearly two decades.

A 2008 investigation by the Basildon Echo found up to 20 workers were being kept in disgusting conditions at the camp, with travellers referring to them as 'dossers' and 'slaves'.

After years of inaction, Essex Police raided Hovefields in December 2021 and rescued 12 suspected victims and nine dogs. Five people were arrested, but no charges were brought.

Local residents told the Mail they have seen foreign nationals at the site and fear they could be being exploited.

'It's got much worse at Hovefields since the time it was always in the papers,' one man in his sixties told the Mail. 

'The travellers have crammed so many mobile homes side by side we have no idea who is living in them.

'On one pitch they seem to be mainly foreign nationals coming in and out on motorbikes doing delivery jobs. On another we have seen people who look like they could come from India or China.

'We have no clue who these people are or why they are living there so the police and council really need to look at this.'

Immigration Enforcement officers receive specialist training to spot the signs of modern slavery. 

In 2024, Basildon Council said it had been working with Immigration Enforcement and police to investigate Hovefields and found two foreign nationals living in caravans as tenants of an unidentified landowner. 

A spokesman said investigations were difficult because the migrants were often 'frightened and vulnerable'. 

The threat of modern slavery at traveller sites is being taken seriously at the highest levels of law enforcement, including the National Crime Agency (NCA).

'Labour exploitation within secluded environments – including cases within traveller sites – remains a high harm model of modern slavery and human trafficking,' an NCA source said.

'This form of exploitation occurs where victims provide services directly to offenders, to develop or maintain their own property, or provide domestic services such as cleaning and care.

'This often takes place alongside exploitation within offender-owned businesses, generally operating within informal sectors such as home improvement and maintenance services.'

The source said foreign nationals, 'particularly those without regular immigration status' were vulnerable to being forced into slavery.

By their nature, traveller sites are often closed to outsiders, meaning the reality of what goes on inside them remains murky.

So should we expect to hear of further horrors? That much seems inevitable.