A bankrupt businessman has been convicted of a conspiracy to steal fuel from underground pipelines.

One site targeted by Roger Gull and others was the former country residence of the then Liberal Democrat leader Nick Clegg.

Maidstone Crown Court heard there was an “impromptu refinery” in the grounds of Oveney Green Farm on Chevening Estate in Sevenoaks, to syphon off fuel from the pipelines.

A fenced compound was set up as part of a £1 million scam to steal hydrocarbon oil.

When police officers carried out a raid in August 2014 they found a lorry trailer and two metal shipping containers, 21 1,000-litre plastic containers and a hose running from a multi-commodity fuel pipeline and along the perimeter of the field into the compound for a distance of 250 metres.

Prosecutor Dale Sullivan said the containers were used as a makeshift workshop where the fuel being syphoned from the high-pressure pipeline could be identified and tested.

The fuel was red diesel, used in the agricultural industry.

Chevening House, a Grade II listed property in extensive grounds, was the official residence of Mr Clegg at the time of the theft.

Owned by a board of trustees, the Prime Minister can nominate either a Cabinet member or a descendant of King George VI to live there. It is currently the official residence of Foreign Secretary Boris Johnson.

Mr Sullivan said millions of litres of fuel were stolen from “incursion sites” in the UK between June 2013 and November 2014.

The overall value, including repair and clean-up costs, ran into millions of pounds.

Gull, 51, set up a number of the incursion sites and arranged storage, processing and distribution of the fuel, said Mr Sullivan.

His son Ryan Gull, 28, was accused of using his position as director of a number of family businesses operating under the Rykel name to launder money from the fuel sales.

Company vans and trailers were also alleged to have been used.

Employee Thomas Campbell, 58, was alleged to have been responsible for transporting the fuel to storage and its onward sale.

But Ryan Gull, of Upminster Road North, Rainham, Essex, was acquitted of converting criminal property of £50,421 and £67,577 from fuel sales and Mr Campbell, of Richardson Avenue, Hurlford, Kilmarnock, Scotland, was cleared of conspiracy to steal.

Roger Gull, also of Upminster Road North, Rainham, was cleared of possessing criminal property of £26,000,

The three denied all of the charges.

Judge Philip St John-Stevens adjourned sentence on him until September 6.