Asking people if they were suffering from SAD or 'skint and depressed', the email painted a grim post New Year's Day scenario of broken new year resolutions with nothing to look forward to, and asked if your "bank account looks like Nick Leeson's been at it".
The campaign promoting Egg's credit card had a simple solution -- blow everything and put it all on the credit card.
"We've got solutions to brighten even the darkest January evening. Find a bargain night out, a pampering fixer-upper or just say 'to hell with it' and stick it on the card."
After blowing the cash and have a wild good time, Egg suggested potential customers should probably not bother turning up for work.
"Take a duvet day. Can't face the thought of work? Then throw a sickie and bed down for the day, where all you need to think about is how to pamper yourself next," the email said.
The Advertising Standards Authority backed up public complaints and claimed that, although it was written in a style that the audience may be familiar with, it could encourage people to incur debt at a time when they could least afford it. It also said that the ad was irresponsible as it could encourage absenteeism from work.
Egg claimed that the newsletter was a one-off and the language used was intended to appeal to 25-40 year old upwardly mobile customers, who were familiar with their use of edgy and quirky communications.
It believed that phrases such as "your bank account looks like Nick Leeson's been at it" would be seen as obvious exaggerations and would not be taken seriously.
Egg said that it did not believe that the target audience would be influenced by the newsletter to an extent that they would incur debt or feign illness to take time off work. It agreed not to repeat the approach.
Egg's latest £10m advertising campaign, which broke this month, exploits consumers' mistrust of banks and encourages people to take control of their finances.
In one execution, created by Mother, a woman is explaining a pyramid scheme called the Fellowship of Life. She tells her audience how she persuades consumers to send her money and then never makes any for them.
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