The dump at Aldermaston was the size of five football pitches and piled with 65,000 tonnes of construction and demolition waste before it was shut down in 2008.

The Environment Agency raided the site in October 2008 seizing an unlicensed handgun and ammunition, other weapons, stolen vehicles, plant equipment and over £50,000 in cash.

Hugh O’Donnell, 64, of Reading, was subsequently imprisoned in 2009 for four and a half years for possession of the illegal firearm.

Upon his release from prison last week O’Donnell was coincidentally sentenced in Isleworth Crown Court to four years in prison for money-laundering and 22 months for waste offences to be served concurrently.

His accomplices Robert Evans, 59, and Peter Lavelle, 28, both of Reading, received 2 years and 18 months respectively for money-laundering, and 14 months and 12 month respectively for waste offences – all to be served concurrently.

Judge Edmunds QC said: “This was deliberate, calculated offending on an industrial scale .. for profit.

“You carried on in the teeth of attempts to stop you, and with the clear intention of making as much criminal profit as you could before you were stopped.

“The attitude shown to the enforcement authorities was dismissive and obstructive.”

Angus Innes, Environment Agency Principal Solicitor, said: “O’Donnell’s illegal waste business netted millions of pounds in profit by taking skips or lorry loads of construction and demolition waste into the Aldermaston site to be dumped in an illegal landfill.

“This investigation has been one of the biggest and most complex ever undertaken by the Environment Agency, using intelligence and forensic science to proactively target an organised criminal gang running an illegal waste site.”

Judge Edmunds QC said: “There were many persons from whom the waste originated who paid a commercial rate for the disposal and believed it was being disposed of responsibly.”

Innes said: “Businesses producing waste – such as those in the construction and demolition industry – need to take extra care to ensure their waste is not being dumped illegally at sites like this one”.