Do you bank with HSBC?

I was trying to use my credit card today and it was declined. At almost exactly the same time I got a call from HSBC wanting to verify who I was.

The lady on the other end of the phone wouldn't give away many details, apparently in case it were to prejudice any potential legal action! I did manage to glean that they have lost the credit card details of quite a few people. They let my transaction through, but have now cancelled my card and are sending me a new one. As soon as they hung up they rang me back on my mobile as a "second check". Someone has tried to the address on my account too.

Clearly some major cock up has taken place. If you are an HSBC customer I would get in touch and find out if you are affected. I wonder if it will break in the mass media? Or they will own up and tell their customers?