The trial was originally scheduled to be commenced in December 2008, but, after the existence of a report critical of the trial became known, the trial was pushed back. On 11 February 2009 a new filtering trial was announced, initially with the ISPs iPrimus Telecommunications, Tech 2U, Webshield, OMNIconnect, Netforce and Highway 1. Testing with each ISP will take place for at least six weeks once filtering equipment has been obtained and installed, and iPrimus expects the trial to begin in late April or early May with five or ten thousand participants. The trial will be opt-in, with ISPs asking for volunteers, although all WebShield customers already receive a filtered service. None of the top three ISPs, Telstra, Optus and iiNet, have been included in the trial, although both iiNet and Optus did expect to be involved at a later time. iiNet withdrew itself from consideration for the trial in March 2009, with Michael Malone giving as reasons the media storm around the leaked blocklist, the changing nature of policy, and "confused" explanations of the trial's purpose.