7.26pm update: Menzies Campbell has said he won't be standing against Kennedy. He told Sky News:
"I've said on several occasions previously that I wouldn't stand against Mr Kennedy and I'm content and happy to confirm that once again this evening." You can see our gallery of possible Lib Dem leadership contenders here:
6.21pm update: Well it was option number two: Charles Kennedy has called a leadership election while admitting on live TV that he had been treated for a drink problem for the past 18 months. The inevitable jockeying for position has begun: although Mark Oaten has ruled himself out of the vote, there is no word yet from fellow frontrunners deputy leader Sir Menzies Campbell and chairman Simon Hughes.
4.44pm: After three months of sniping, which the Christmas season of goodwill to all men did nothing to alleviate, Liberal Democrat leader Charles Kennedy is making what is called a "personal statement" at 5.45pm. This could mean any of several things:
1. Resignation as leader. Possible, but a slightly odd and undignified time to do it - just hours after pledging to fight any challenge to his leadership.
2. Announcing a leadership election. According to the rule book, Mr Kennedy can call one of these at any time - despite being re-elected unopposed as leader by the full party membership for a full third term only last summer. This would smoke out any would-be rivals, and Mr Kennedy has always insisted he would stand again.
3. A vote of confidence in his leadership. A high-risk "put up or shut up" strategy. Mr Kennedy would have to win at least half of the parliamentary party - that's 31 of 62 MPs - to survive. But anything short of an overwhelming majority would fatally weaken him.
4. Something completely unexpected I've not thought of.
