Analysis By Nick Assinder Political Correspondent, BBC News Website

Mr Kennedy: Throwing down gauntlet

Charles Kennedy has met the latest assaults on his leadership with a defiant and, in his own words, "aggressive" response.

To all intents and purposes, he has challenged his internal party critics to put their money where their mouths are and launch a leadership campaign.

If they want him out they will first have to win enough support from Lib Dem MPs to stage that contest. Then they will have to face him in open battle.

He insists he has no intention of standing down voluntarily but intends to "up his game" and offer "direct and aggressive" leadership.

His defiant remarks suggest a man who is confident he has the majority support of both his grassroots party members, who get the vote in any leadership contest, and his MPs who would need to spark it.

He has probably calculated that his critics currently do not have the nerve to challenge him - so there will be no contest, yet - and that, even if they did, he would win it in any case.

Internal feuding

His detractors certainly do not have one obvious candidate waiting in the wings who they could all rally around, despite the bandying about of various names from the different wings of the party.

And, it would seem, he does retain the support of the party's grassroots members, suggesting they might not take too kindly to a leadership contest at this moment.

The timing is also important. Along with his challenge, Mr Kennedy issued a warning about the damage such a contest would cause.

It would pitch the Liberal Democrats into a prolonged period of internal feuding just when they should be turning all their energies into fighting the vital local elections in May. He knows that is a genuine worry.

The danger, of course, is that it might force his detractors to move against him sooner rather than later in an attempt to win some sort of election bounce from a new leader.

Orange book

It is also dangerous as it offers his challengers a deadline, and an event on which to test his leadership.

Meanwhile, however, Mr Kennedy has signalled he is about to address one of the greatest criticisms of his leadership � that he has failed to weigh into the philosophical debate over his party's future.

For many that has been a strength as it has held the party together during a period of genuine internal debate, centred around the backers of the "Orange Book" - led by the likes of MP David Laws - who want the adoption of a liberal, free market economic policy.

Others, however, believe this is an issue that has to be taken head-on if the party is to offer clarity.

Mr Kennedy has now announced he will be making a major speech on precisely that subject within the next few days.

Gauntlet

That will provide an early test of whether he has satisfied demands for him to up his game.

Secondly, he is promising to step up his attacks on new Tory leader David Cameron who, he argues, is simply offering more Blairism.

But he must know he has a major battle on his hands and will need to produce the goods.

The criticisms are not confined to anonymous briefings to the media, as he has suggested, but have come from senior party figures in public.

Mr Kennedy may calculate his gauntlet will not be picked up at the moment... but the future remains far less certain.