yes, its one of the 2 openreach modems, so is a 50% chance you already have it but locked. I unlocked the one BT gave me, its trivial to do.
http://huaweihg612hacking.wordpress.com/
see on the right hand side is links to instructions.
Basically download the unlocked firmware. (same as default firmware except port 80 is opened on the firewall for access to gui and 23 for telnet).
disconnect it from the internet, power off and plug in directly to pc/laptop with lan cable, make sure pc is on static ip.
when you power it on you have to hold one of the buttons down (i think reset button says in the instructions), this puts it in recovery mode, and from there you can flash the unlocked firmware.
Once unlocked connect back to the dsl cable and router as normal, it will come back online. But also connect a 2nd lan cable to the 2nd lan port on the hg612 (the one that comes taped over, remove the tape), and then you can access the gui/telnet on 192.168.1.1.
After that also disable QoS to give a 10% boost to upload speeds.
You can buy these unlocked on ebay if you want also.