Tax payers have been warned to beware of more frauds using the name of HM Revenue and Customs (HMRC).
Fake e-mails ask people for personal details
At least eight different frauds are now listed on the HMRC website, compared with just one last December.
Among them are ones involving bogus anti-terrorist certificates, tax rebates, export clearance and even one offering compensation to fraud victims.
An HMRC spokesman said very few people had fallen for these, but added that the perpetrators were very devious.
"There is an emerging pattern - when we close one down they go to another channel," he said.
"Their audacity beggars belief," he added.
The common theme among the frauds is that they attempt to trick people into revealing important financial information about themselves, such as bank account details, or try to trick them into handing over money.
The usual method is to send the tax-payer an e-mail, purporting to come from HMRC, or even to phone the person directly.
Fake names in e-mails can include "Inland Revenue Board", "Inland Revenue and Customs Board" and "Inland Tax Clearance."
A fraud involving a non-existent "anti-terrorist certificate" tells people that they have to buy one before customs officers will let an item in the post be sent to them.
Another fraud involves e-mailing people and asking them to supply personal details for a supposed compensation claim - to "Her Majesty Customs and Revenue Commission" - if they have been the victim of a previous fraud.
Fraud from abroad
The HMRC says it relies on recipients using common sense and good judgement to ignore these.
The frauds, always originating abroad, are often written in garbled English.
"Sequel to complaints received as regards some foreigners," says one letter, supposedly from the head of HMRC.
The HMRC spokesman reiterated that the body "never asks for information over the internet".