Officers investigating the theft of 30,000 litres of fuel from pipelines running below the Deputy Prime Minister's home in Kent have raided two suspected diesel laundering plants.

The fuel was diverted out of the 120 mile long pipeline after thieves drilled into it just outside Chevening House near Sevenoaks, the country residence of Deputy Prime Minister Nick Clegg.

Today HM Revenue and Customs has revealed that two suspected laundering plants, capable of evading an estimated £12 million in duty between them, have now been dismantled in Essex and Merseyside.

The discovery of the plants, which can produce 20 million litres of illicit fuel a year, is connected to activity by Kent Police who are investigating the theft of the fuel from Chevening House.

During a series of combined operations involving HMRC and Kent Police, officers searched premises in the Upminster and West Thurrock areas of Essex where they discovered a laundering plant.

HMRC supported by officers from Merseyside Police also searched commercial premises in the Bootle area where they discovered a second laundering plant in an industrial unit.

Pat Curtis, national oils co-ordinator, HMRC, said: “Every illegal diesel laundering operation typically generates tonnes of toxic waste and robs UK taxpayers by evading fuel duty.

"Taxpayers are not only missing out on the stolen tax that ends up the pockets of the criminals, but will have to pay the substantial clean-up and disposal costs.

“Buying illicit fuel not only funds crime, it supports and encourages these dangerous activities within our communities and we will continue to work with our partners in the Police to target this criminality, which costs millions in lost taxes every year.”

During the operation officers seized over 14,000 litres of laundered fuel, 136 industrial containers, tanks and tubes and 50 gallon oil drums believed to contain waste product inj Upminster, Essex.

In West Thurrock a tanker containing 5,000 litres of contaminated diesel, 10,000 litres of diesel in a storage tank, ten 1,000 litre industrial containers, a 40ft curtain-sided lorry, two lorries and a van.

In Bootle, Merseyside officers seized over 30 1,000 litre industrial containers with many containing laundered fuel waste, over 60 further containers, products for laundering fuel, 100,000 litres of untested diesel and a tanker truck.

On Thursday, five people were arrested in connection with the theft of fuel from below Chevening House

Investigations into the seizures are continuing.