An entrepreneur whose lavish home was used in scenes from the Oscar-winning film The King's Speech and for a less mainstream "porn disco" has been jailed for a multimillion-pound fraud.

Self-styled "Lord" Edward Davenport, 45, was the mastermind of an "advanced fee fraud" scheme in which scores of businesses were ripped off.

Davenport – who owns Sierra Leone's former High Commission in west London – set up Gresham Ltd in 2005 and pretended it was a respectable business with 50 years' experience of sourcing huge commercial loans.

"To outward appearances it was long-established, wealthy and prestigious," said Simon Mayo QC, for the prosecution at Southwark crown court.

"It operated from expensive London premises and had a balance sheet showing significant assets.

"It had a flattering corporate brochure and used headed notepaper that lent an image of corporate credibility.

"That image, however, deliberately cultivated by these defendants, was entirely false.

"In truth it was a company which had only been set up by Edward Davenport in late 2005.

"It was essentially worthless. Its only business was fraud."

Davenport, of Portland Place, central London, was jailed last month for seven years and eight months along with his lieutenant, Peter Riley, 64, of The Old Bakery, Brentwood, Essex.

They were convicted of a single count of conspiracy to defraud along with Borge Andersen, 66, of Roland Gardens, south Kensington, south-west London.

Andersen was jailed for 39 months at the same court on 12 September. He was also disqualified from being a company director for seven years under Section 2 of the Directors Disqualification Act.

Their convictions, following a three-month trial, can be reported for the first time after a judge lifted an order.

Davenport hit the headlines last year when Westminster council banned him from using his historic home for activities including a "porn disco", a sex party and pole dancing lessons.

The five-storey, 110-room house was also used for film shoots, a fashion show, a wedding, a nightclub and a masquerade ball.

His swimming pool was reportedly filled with Cognac so revellers could row through it.

But the Serious Fraud Office arrested him in December 2009 after gathering evidence that Gresham had promised to fund loans worth £500m.

From 2007 to 2009 Gresham Ltd had received more than £4.5m from unsuspecting clients.

The fraudsters made their money by fooling clients into paying tens of thousands of pounds for due diligence and deposit fees.

Across the world businesses were collapsing after entering into big deals on the false promise from Gresham that their money was only days away.

In Austria, two victims had contractors waiting to start work with diggers after Gresham promised to find €32m (£27.4m) to fund a leisure resort. No money materialised.

In India a businessman from Bellary Steels paid Gresham £285,000 to finance €183m. Nothing materialised and the victim "suffered crippling losses" of £825,000 and now owes €11m, the court heard.

There were at least 51 victims.

Davenport, known as "Fast Eddie" and pictured on his website with dozens of celebrities including Simon Cowell, the actor Hugh Grant, Sarah Ferguson and the justice secretary, Kenneth Clarke, kept his distance from the legwork and operated under a false name, James Stewart or Stuart.

He launched the fraud, remained in overall charge and did not "leave many footprints in the snow for himself", not wanting to risk his champagne lifestyle which included parties with the stars and a property in Monaco.

Davenport, supported in court by his girlfriend and 78-year-old mother, was happy to give orders to Riley, the son of an alcoholic schoolteacher.

Judge Peter Testar described Riley as "an accomplished conman" who could lie with incredible ease and skill to clients desperately waiting for their money.

Riley blamed many of the delays on a lawyer in Monaco called Louis Martin.

But Martin did not exist – it was Riley introducing one of many fictitious characters to aid the scam.

Riley set up an email address for the non-existent Martin and to add credibility wrote emails from him in broken English.

The judge said of the grandfather-of-one: "He strung along borrowers on a huge scale with bare-faced lies."

Of the victims, he added: "The stress and anxiety these people suffered were enormous and their lives have been grievously affected by this fraud.

"Some of them will never recover from that … It was a professional and sophisticated fraud which had a great impact on the victims and each of these two defendants had a significant role to play."

Andersen, a Danish national, will be sentenced after his defence obtain medical reports for his various illnesses.

He was "generally perceived as the most articulate and plausible of the fraudsters", said Mayo.

He made loan offers and provided bogus explanations for delays with money.

According to internal Gresham accounts created by Riley, Andersen received £159,564 from the fraud, Riley £695,407, and Davenport £773,000. The court heard that £349,025 has vanished from the accounts and cannot be traced.

Davenport and Riley were banned from being company directors for 10 years after their release and a confiscation hearing was listed for 2 May next year.