Business tycoon Asil Nadir would have needed banknotes 300 times the height of Nelson's Column to balance the books of his failing empire, the Old Bailey heard on Friday.
Nadir, who is accused of siphoning off £150m from Polly Peck International, told investigators his mother put the money back in Turkish lira (TL).
He claimed she and others made deposits to a bank he owned in Northern Cyprus.
But Philip Shears, QC, prosecuting, told the jury the claim was "not credible".
He said one deposit slip in June 1988 to balance a £6m transfer from PPI suggested 148.8m TL were deposited in 100TL bank notes.
"Such a huge quantity of bank notes is likely to have weighed 135,185kg - over 135 tonnes," said Mr Shears.
"If the notes were piled on top of each other, they would reach a height 300 times the height of Nelson's Column.
"What is also open to question is how the defendant's mother was physically able to transport and deposit such vast quantities of banknotes on a regular basis.
"Without being flippant, we are now in the realms of forklift trucks and vans stuffed full of banknotes.
"Moreover, from where did she or others get all this money?"
Nadir, 70, of Mayfair, central London, denies 13 specimen counts of theft amounting to £34 million between 1987 and 1990.
He was arrested and was due to stand trial in 1993 but left Britain for Northern Cyprus, only to return in August 2010.
Mr Shears said his "fleeing the country before his trial in order to avoid prosecution and trial, remaining out of the jurisdiction for some 17 years" was evidence of his dishonesty.
The jury has heard that PPI was put into administration in October 1990 with debts of £550 million.
The administrators were unable to track down the large amounts sent to Northern Cyprus.
The prosecution said documents about the deposits said to have been made by Safiye Nadir were fake.
Accountants who went to Northern Cyprus were unable to speak to Mrs Nadir and had difficulty with Nadir's employees.
Mr Shears said: "Administrators were met with obstruction, and inaccurate and inconsistent accounts and explanations."
But Kemal Birgen, a former bank manager of IBK who has since died, implicated the finance director of PPI subsidiary Unipac and bank workers.
Mr Shears said the cash deposit claim "simply beggars belief". Mr Bergen said the bank did not have space for such large deposits.
He added: "Mr Birgen stated it did not happen - with regard to Asil Nadir's mother, she never had up to £70 million in her deposit account, and had no knowledge of 300 billion lira passing through the accounts."
Mr Birgen, manager of IBK from 1982 to April 1991, said he had been forced to resign.
He was interviewed by Christopher Howell for the administrators in July 1991.
Mr Shears said: "He later told Mr Howell that he had been threatened, had had dead chickens delivered, his house had been petrol-bombed, and an abusive phone call was received while Mr Howell was present."