Barclays face an investigation by the Information Commissioner's Office (ICO) as a result of the recent BBC programme "Whistleblower", which placed an undercover reporter in a Barclays call centre and one of their high street branches.
Whistleblower alleged that call centre staff accessed private customer files, and made sales calls to people who asked not to be contacted.
The ICO said that the allegations were a cause for concern.
The BBC placed their undercover reporter in the Doxford call centre in Sunderland, where she found examples of mis-selling, employees lying to customers and security failings.
"I've seen customers misled, lied to and treated with contempt. I've seen people charged for financial products they neither asked for or knew they had."
The ICO has asked Barclays for the results of an internal inquiry, and for a copy of its policy on telephone sales.
Barclays said in a statement:
"We take the allegations made by the programme very seriously and are conducting our own internal investigation. Where there has been improper behaviour we will take action to improve what we do. Of course we will also fully co-operate with the Information Commissioner's own investigation."
To add to Barclays humiliation Reuters report that it faces a US investigation by the Securities and Exchange Commission (SEC), into allegations of insider dealing by bank staff who served on bankruptcy committees.
The SEC will look at trading activity between 2002 and 2003 by a proprietary trading desk at Barclays.
A separate lawsuit filed against the bank in March by a former employee alleges that Barclays' U.S. distressed debt desk, which deals in bankrupt company bonds, traded debt after "potentially gaining nonpublic information" through bankruptcy creditor committees.
This has been topped off by the news that a group led by Royal Bank of Scotland says that it plans to go hostile if necessary with an offer for ABN AMRO, the Dutch bank that has already agreed a deal with Barclays.
The hostile bid is estimated to be worth around £49BN, compared with the £45BN offered by Barclays.
Not a happy week for Barclays!