The warning was prompted by a spate of inquiries from the public and institutions in the UK and abroad over certificates of deposit for more than $1bn, supposedly drawn on the Bank of England. In fact the Bank issues no such certificates.
Ian Watt, head of the Bank's investigations unit, said: "An investor might come across them if he or she is being offered paper when they're trying to borrow or perhaps to make an investment, and one of these certificates might be produced to them, suggesting that an unnamed individual has a very large sum of money deposited with the Bank of England."
Mr Watt said that so far the Bank was not aware of anyone falling for this type of fraud, but warned: "There are intermediaries who are putting out this forged paper and the worry is that someone might eventually be taken in by it, which is the reason why we are very anxious to get the news around and protect the public generally."
Earlier this year two people were arrested and charged with a similar type of fraud, advanced fee fraud, after an investigation called Operation Labis. A number of people operating a bank in Torquay were offering multi- million-pound loans in exchange for a cash fee up-front. The loans never materialised.
Mr Watt said the present spate of forgeries was connected with this type of fraud. "We are in touch, of course, with the police and they from time to time refer documents to us to determine whether they are genuine or not."
The forged Bank of England certificates have surfaced abroad just as often as in the UK.