Despite a shaky start to the Halo 3 beta, where problems were reported by fans trying to download the three levels of the game, the all clear has been given after some frantic work by Bungie and Microsoft.

The problem seemed to centre around the beta keys given to fans who bought copies of Crackdown and they were locked out for most the morning, though now, this afternoon, the Bungie website has reported an all-clear.

"We're happy to announce that effective immediately, a title update for Crackdown is available on Xbox Live that will fix the issue that previously prevented you from downloading the beta", said the site administrator.

"The Microsoft team just deployed this fix and when you launch Crackdown you should receive a prompt to download the update."

It’s not all good news however as Bungie also report the possibility of delays in the download, saying that it could take up to 4 hours. To placate fans Bungie have extended the beta period for an extra 4 days. Now it will finish at 11.59 on June 10.