Why won't my HTC Mini charge?

[AC Question]

My phone battery died this morning and when I plugged it in to charge, it was struggling to get past 1% and the LED was flashing orange. Eventually, it got as far as 8%, at which point I turned it on. The phone then said it needed to be switched off while charging as it was using too much power. So I turned it off and it hasn't charged since. It says it's charging, and it recognises the charger alright. I've tried numerous different cables etc but the problem seems to be with the phone. Anyone have any ideas?