Bank customers are being warned again about "phishing" scam e-mails, after a recent increase in those falling victim to the internet menace.
High Street banks have been targeted
Internet security firm MessageLabs said it had stopped 215,643 "phishing" e-mails last month compared with just 279 last September.
Phishing is used by fraudsters and organised crime to gain bank details.
MessageLabs' information security analyst Natasha Staley said the figures were "just the tip of the iceberg".
'Tip of the iceberg'
The Association for Payment Clearing Services (APACS) told BBC News Online last month it was worried by a surge in phishing scam e-mails over a period of days.
Phishing "scamsters" pose as a bank to request personal details as part of a bogus "security check".
If the customer falls for the e-mail scam and enters his or her details, the scamsters can empty that account or use it to launder money.
MessageLabs' information security analyst Natasha Staley said: "We are only monitoring our customers' emails so this is just the tip of the iceberg.
"The true extent of the problem is just impossible to
Its own figures hit a peak in January when it stopped 337,350 "phishing" e-mails.
A spokeswoman for the National High-Tech Crime Unit (NHTCU) warned that the scam companies were using ever more ways to expand their illegal earnings.
The "phishing" gangs were now using "mules" recruited
through online job websites to withdraw the cash from the duped customers' accounts before it is then wired to the criminals, she said.
"What we are seeing now is that instead of money going straight from the account into the criminal's account what they are doing is 'washing' it through
these `mules'," she said.
In the past, customers of many of the UK's major High Street banks such as Natwest, Barclays and Lloyds TSB have been targeted.
Banks and the NCTHU are working around the clock to close the phishing sites.
The spokeswoman for the NHTCU, which is investigating the fraud, said high street banks had been working closely together to combat the scam.
"They got together quite quickly at the beginning and I have seen the marketing material that they are sending out," she said.
"There is not a lot more they can do apart from warn customers of the danger.
"A lot of people are not falling for it but some people still are.
"The problem is that it is such an easy thing to do. You just send out loads of spam emails and hope that 1% of them will hit."