Simon: not quite accurate. While I suspect that the OP is referring to holding 2 X Blue regular passports simultaneously - which I suspect is not allowable - it is possible to have two passports issued in your name - one regular (blue) and one special (green). However in order to receive a Special passport one would need to meet the requirement. It is regular practice amongst federal departments to turn in your blue passport in order to take receipt of the green passport while on travel as a representative of the Federal Government. Thus one only holds one passport at a time.

cheers, MWAC