Forsyth, 59, was remanded in custody by Mr Justice Tucker for pre-sentence reports; a defence application for bail was turned down. The judge warned her to be under "no illusion as to the likely nature of the sentence".
Forsyth,, from Great Dunmow in Essex, had denied two charges of handling the stolen cash in October 1989.
Lawyers for Asil Nadir are now expected to apply for the pounds 30m theft charges against the fugitive businessman to be thrown out.. His solicitor Peter Krivinskas said Nadir planned to apply to the High Court for the case to be dropped on the grounds of abuse of process. Nadir alleges general abuse, but the claim is understood to centre on the Serious Fraud Office's handling of the case and prejudicial media coverage.
The jury's verdict today, in essence, also convicts the fugitive tycoon, in his absence, of stealing from Polly Peck - a charge which he was facing when he jumped bail three years ago, four months before he was due to stand trial, and fled to North Cyprus..
The jury of seven women and five men, who deliberated on the verdict for nearly 12 hours, were told that before they could find Forsyth guilty that the Crown had first to prove that Nadir had stolen the money.
As chairman of South Audley Management (SAM) Forsyth managed the Nadir family's private businesses and wealth. She had helped Nadir to siphon cash along a circuitous route through Swiss and English bank accounts to pay his private debts, including a large share-dealing bill.
The prosecution said that in October 1989 Forsyth went to Geneva to withdraw pounds 400,000 in cash. The following day she deposited just over pounds 300,000 in a different bank with instructions that it should be transferred to AJ Bekhor, a London stockbroker to whom Nadir owed money. Forsyth returned to Britain the next day and gave the remaining cash to a chauffeur to bank. It was to pay money owed by Baggrave Farm - a Leicestershire estate owned by Nadir.
Forsyth maintained she had been sent to Geneva by Nadir simply to "hold the hands" of his bankers there following the Black Friday crash on the US markets. While in Geneva she said she was asked by a former director of SAM to withdraw the cash and transfer it to London. She claimed she had no knowledge of the monies' origin and had no reason to believe anything she was doing was unlawful. Geoffrey Robertson QC, her counsel, said Forsyth had been simply doing her duty when she was ordered to carry out the transaction.
The SFO say they are intent on prosecuting Nadir, although he remains a fugitive in Cyprus. A warrant is out for his arrest and he has been placed on Interpol lists.
Forsyth had herself gone to Northern Cyprus in early 1992. She had been questioned by the SFO the previous year, and in the summer of 1992 she learnt that the SFO wanted to interview her again, and in September 1994 she decided to return to Britain to face the music.
Forsyth was on bail throughout the five-week trial and was supported on many days by her 89-year-old mother.
Asil Nadir had been regarded as one of the wealthiest men in Britain. His pounds 1.3bn PPI empire collapsed soon after the Serious Fraud Office raided SAM'S Mayfair premises in 1990.
As a businessman, Nadir had won Queen's Awards for industry, and had been invited to 10 Downing Street several times by the then Prime Minister Mrs Thatcher, Mr Robinson said, adding that Nadir had also contributed large sums to the Conservative Party.