Campaigner Len Gridley recalls visiting a Smithy Fen public inquiry in 2004.

He said: "Dale Farm travellers were there. They covered their faces when they saw me, but I knew what was going on."

Crays Hill and Cottenham residents have long suspected links, and villagers' anecdotes point to travellers using both sites.

An Oak Lane traveller recently heard renewing car tax in the Hemmings store, London Road, Crays Hill, had a vehicle registered to Smithy Fen.

Bridget Quilligan, 39, is pleading to stay at Dale Farm, but Cottenham residents claim she has been spotted several times driving with L-plates at Smithy Fen.

Basildon Magistrates' Court fined her for driving without L-plates along Oak Road last June.

A woman living near Smithy Fen said: "I saw receipts thrown out by travellers. Some were for items bought in Billericay."

Residents from Crays Hill and Cottenham recognised travellers in the BBC Gypsy Wars series.

Lyn Wood and a middle-aged Crays Hill woman recognised a number of people in the Smithy Fen episode as being regulars at Crays Hill.

Ms Wood said Smithy Fen elder Roger Slattery, 59, has been to Crays Hill and she recognised Ann Sheridan on an Anglia TV news story about an illegal plot at Smithy Fen.

Evidence of links is also found in planning documents.

Many names on planning applications for both sites are identical, including O'Briens, Quilligans and Slatterys.

Basildon Council records say officers were unable to trace Ellen Quilligan at her illegal Dale Farm plot, despite a number of visits.

A woman of the same name bought a new illegal plot at Smithy Fen last August.

At public inquiries, travellers have admitted moving between the sites.

Nora O'Brien, who has fought to stay at Orchard Drive, Smithy Fen, for three years said she came after living at Basildon.

Kathleen Gammell told a Smithy Fen appeal in July 2005 she previously lived on a plot owned by her son at Crays Hill.

John Sheridan, 37, who runs AA Sheridan Builders from Smithy Fen, told the appeal he had lived at Crays Hill with relatives.

Overlaps also occur at Wolverhampton's Low Hill estate where the clan has several homes, and a Roger Slattery, 59, set up the business Ashtock Ltd in 1998.

Some Dale Farm and Smithy Fen travellers' names still appear on the electoral roll there.

It's not just pensioners at the site Travellers claim just nine men aged between 18 and 60 live at Dale Farm - despite reports of it being crammed with young men, flashy 4X4s and work vans.

Thirty out of 40 appellants were single mothers or pensioners on benefits, according to information supplied by travellers at the last appeal.

A similar pattern exists at Cottenham.

Residents believe wealthy clan members buy green belt and use poor or elderly relatives to win planning permission on human rights grounds so they can be sold or rented.

Basildon and South Cambridgeshire councils seem reluctant to investigate, despite suspecting links between the sites.

A South Cambridgeshire spokeswoman said: "We liaised with Basildon, but the problem is one of identification.

"It is difficult trying to prove identity and we don't have the resources for that level of investigation."

Basildon Council leader Malcolm Buckley said: "I recognised people in the BBC3 Cottenham documentary, who I believed were from Dale Farm.

"There are contacts between authorities and certain information is shared."