5.16pm: Neil Perry in Oslo just sent me this worrying development. I‘ll try to get more details:

A man disguised as a police officer began shooting where youth were attending a Labour party conference at Utoya, Prime Minister Jens Stoltenberg has just confirmed.

He said there is a ‚critical and serious situation‘ but he is safe.

He was speaking on the phone to Norwegian TV station TV2.

UPDATE: This post was amended as Stoltenberg was not present at the conference as previously stated. He had been due to attend it but did not go.