Police say hundreds of victims' lives have been devastated after falling prey to the fraudsters controlling a fake share scam.
A woman from Hampshire was scammed out of a six-figure sum over a period of two-and-a-half years by a series of cold callers.
The woman who wants to remain anonymous was conned into ploughing thousands of pounds into bogus investments in carbon credits, rare earth metals and gold.
She said: "When my marriage broke up seven years ago I was very conscious that I was now setting out on my own to make my own decisions. I wanted to start investing what I had very carefully to build a pension for my daughter - that is what mothers do.
"When I had the first call about investing in carbon credits I thought that was the beginning. I was very interested in the idea so I agreed to invest and I was then sold some more carbon credits and the same seller, who by this time had become quite a pal, then suggested investing in rare earth metals.
"I bought rare earth metals over a period of a year and that led me onto a company which was offering shares in anti-malaria products which I thought was the right thing to invest in as well."
A few weeks after Ms Mayer had invested in the medical products she was contacted by another caller who said he had connections with the "anti-malaria" company and he had heard she was interested in investing for her daughter's future.
"The caller said he had been in the financial markets for 18 years and he had been a financial advisor. He suggested that I bought gold and he said it would be a wonderful reserve for me and a sound investment. Over a period of many weeks I felt I got to know him quite well. He was very helpful and thoughtful and he kept in touch regularly."
After Ms Mayer had invested in the gold, the same caller told her about a gold mine flotation, which he said was backed by a well-known bank.
When she told him she did not have "that sort of money" to invest, he suggested she release equity from her house because it was an "extraordinary" opportunity.
She said: "Over a period of days I agreed to see if I could get more equity out of my house - which I foolishly did. It was only when that flotation mysteriously managed not to happen that I released that I was deep in it. At every turn my daughter and I realised that I was in it - absolutely hook, line and sinker and that nothing was going to come out of it.
"I felt I had been a complete fool and I had been completely conned. For a time I didn't dare show my face anywhere, I just wanted to hide away. That is the effect this sort of thing has. You lose confidence utterly. I have really lain low for about nine months now. I wanted to hide away from everyone except close friends.
"It has caused a lot of strain between my daughter and myself because she is nervous beyond belief that I am going to do the same thing again and be conned by another person. I am not quite sure where I go from here. I have definitely got plans to get out of this mess and it remains to be seen if I can succeed in doing that. I now spend my entire time working out how I am going to get out of this dilemma."