US 'Catters may consider this a weird question, I'm but constantly fascinated by the differences in US and UK English language usages, so I'm asking anyway.

In the last few years, in correspondence with American friends, or on discussion boards, I've occasionally seen the phrase "my bad". I've taken this to be the UK equivalent of "pardon me" - as opposed to "my bad": manners, luck, breath, ass... :-)

Is "pardon me" a reasonable equivalent? If not - what?

More interestingly, how did the phrase originate - and when? I don't recall seeing it in print until a few years ago - or am I mistaken?