Two men from Belvedere have been arrested on suspicion of involvement in a £3 million fuel fraud.
The suspects, aged 43 and 46, were detained along with two women and five other men during an operation by HM Revenue and Customs.
Around 170 HMRC officers, assisted by the Vehicle and Operator Services Agency and Sussex and Hampshire Police, searched 12 homes, five businesses premises and two petrol stations in East and West Sussex, Kent, Essex, Hampshire and Somerset.
The raid yesterday was focused on the suspected illegal purchase and sale of rebated kerosene and biofuel to motorists as duty-paid road diesel.
The fraud is worth an estimated £3 million in unpaid excise duty and VAT.
David Margree, assistant director in criminal investigation at HMRC, said: "Motorists need to be aware that using illicit fuel can damage and destroy vehicle engines, has a detrimental effect on legitimate fuel traders and deprives the government of money used to fund public services."
All those arrested were questioned by HMRC investigators and released on bail while enquiries continue.
Anyone with information about fuel fraud can contact the Customs Hotline on 0800 59 5000.