The 53-year-old from Edinburgh, who wants to remain anonymous, was targeted in a "sophisticated and elaborate" scam when she received a call at home to tell her that her bank account was being hacked, with instructions on how to move £163,499 into a new account.
Her bank managed to stop £100,000 before it hit the other account but the remainder did go through. Around £20,000 was recovered after an investigation and the bank reimbursed the rest.
Police in Edinburgh are now teaming up with the banking sector to launch a campaign warning people about the scam, known as "vishing".
It comes after a spate of cases in the capital, with 16 people targeted and more than £650,000 of cash stolen in the last month-and-a-half.
All public branches of the main banks will display posters reminding the public never to give out their details if they are cold-called, while police will distribute crime prevention leaflets across the city giving information on how to avoid becoming a victim.
The anonymous victim said she considered herself to be competent and security-aware in dealing with her finances but fell victim to the "well-organised scam probably carried out by professional criminals".
She said the most important part of the fraud was that she thought she had called the number on her bank card which the fraudster had told her to do to report the alleged crime, but they had simply kept the line open and unbeknown to her she was still speaking to them and not to her bank.
"The call to our home came late in the evening just after 10pm when we were tired and unable to go to our branch or speak with a local relationship manager. The main fraudster was articulate, fluent in giving directions about what we had to do to 'protect our money' from criminals whom, we were told, were actively hacking into our accounts trying to move large sums out illegally as we spoke," she added.
"This fear of loss, once created, and the constantly reinforced message that very urgent actions were required, underpinned and drove the way that the subsequent scenario played out.
"There followed possibly the worst five days of our lives during which both the banks and police investigated our case. During this time we had no idea whether or not any of the money that had been stolen would be returned to us."
She said she realised she had a "very narrow escape" as all the stolen money was returned, but her trust in human nature had been "seriously diminished".
She added: "Banking security is clearly everyone's responsibility, the banks and customers alike, and we hope that some of the information we have provided, in some small measure, helps towards saving other people from experiencing such a cruel, harrowing and near life-wrecking ordeal."
Launching the awareness campaign today, Detective Inspector Arron Clinkscales said: "Those responsible for committing these offences are despicable individuals who mostly prey on the elderly and vulnerable members of our communities.
"It is essential that police and the banking industry work together to address this matter and ensure that the public are fully informed on the type of tactics criminals will utilise to obtain their personal details or money."
Chris Wilson, RBS Scotland managing director, added: "Fraudsters work by creating fear that a customer's savings may be under threat. No bank will ever ask a customer to transfer their savings or part of their savings to another account or another bank in order to 'protect the funds'.
"We're delighted to join Police Scotland in this campaign to raise customer awareness around how these scams work."