Sarah Ferguson has reportedly demanded about £45m from Rupert Murdoch, claiming the now defunct News of the World wrecked a series of business opportunities for her when its former reporter Mazher Mahmood caught her in a sting.

The sum is significantly greater than the £25m the Duchess of York was said to have claimed when she initially sued News Group Newspapers, the former publisher of the paper, in 2016.

In newly surfaced court documents, Ferguson reportedly claimed to have lost out on a deal with a private equity firm and work on a film project that would have made her millions of pounds.

Additionally, Ferguson reportedly claimed to have had book deals in the works, while sales of an existing book were hit when she faced “international humiliation” after the sting.

In 2010, Ferguson was secretly caught on camera apparently agreeing to set up a meeting between the undercover reporter, who was posing as a wealthy Indian businessman, and her ex-husband Prince Andrew.

The footage, recorded by the reporter known as the “Fake Sheikh”, apparently showed her accepting £27,600 in advance, telling Mahmood: “I can open any door you want.”

The Duchess of York has claimed Mahmood, who was later jailed for tampering with evidence relevant to an unrelated issue, tricked her into offering to introduce him to Prince Andrew for £500,000.

According to the new court documents, seen by the Mail on Sunday, Ferguson claimed to have lost a deal with the British film executive Graham King to raise “funds for new projects of $125m [£90m]. The commission that would have been payable on funds raised was … £4,373,250”. But the deal fell though after the story ran.

The paper quoted a source close to King as saying Ferguson’s recollection of the deal was “exaggerated”. King did not respond to a request for comment on Sunday.

Ferguson also reportedly claimed to have lost out on a deal to find investors for a private equity firm that was “working to accomplish the merger of the Jaeger and Aquascutum fashion brands”, for which she expected to get a commission between £1m and £1.5m.

She also planned to make millions working as a celebrity endorser and launching products under the name House of Ferguson, working on the animation project Sofi On Safari and a cartoon, Fergie’s Farm.

Both News UK and Ferguson declined to comment on Sunday.