CHRIS FISHER, EDP Political Editor When do sustained efforts to keep the public in the dark not amount to a cover-up? That is a very good question to put to those senior Liberal Democrats who for at least two-and-a-half years individually and collectively did and said nothing to make the electorate aware of the seriousness of Charles Kennedy's alcoholism.

CHRIS FISHER, EDP Political Editor

When do sustained efforts to keep the public in the dark not amount to a cover-up? That is a very good question to put to those senior Liberal Democrats who for at least two-and-a-half years individually and collectively did and said nothing to make the electorate aware of the seriousness of Charles Kennedy's alcoholism.

Matters finally came to a head at the start of this year when he was effectively driven from the office of his party's leader, and the broad truth then came out. And much detail is now being filled in by excerpts from a book, Charles Kennedy: A Tragic Flaw, that will be published just before the Lib Dem conference next month. It is by my Parliamentary Press Gallery colleague Greg Hurst, who writes for the Times.

Rumours and jokes about 'Champagne Charlie's' fondness for booze were commonly heard at Westminster long before he became the Lib Dems' leader in 1999.

Everyone there must have been aware of them, but hardly anyone cared very much. (An exception was his secretary, Anna Werrin, who admits in the book that she was already worried by the time he was elected leader). Paddy Ashdown was then very much the top dog in the third party, and Mr Kennedy was rather a minor player.

When he succeeded Lord Ashdown, the drink problem suddenly mattered a lot more. Much more was expected of him as his party's leader. He had to make key decisions, and he acquired a substantially higher profile. Symptoms of alcoholism became harder to hide totally, and unease spread in his party's top circles.

He was advised by close colleagues in 2001 to get help, and he sought professional advice the following year. The issue was raised on TV in Newsnight that year, and speculation hardened in June 2003 when he missed a major government statement in the Commons about its policy on the euro.

I remember it well. The euro was a big subject for the Lib Dems who stood out by being strongly in favour of Britain joining the single currency. Mr Kennedy's absence was conspicuous - and not least to his frontbench colleagues who had been leaving a space for him in the chamber.

Conjecture that he had missed the occasion because he was seriously the worse for drink was dismissed by Lib Dem spokesmen. But the concern at the top of his party was so strong that a meeting was organised the following month in his Westminster flat at which he was persuaded to go public, the very next day, about his drink problem.

Had he stuck to that, it might have all worked out better for him. But he changed his mind. And the problems continued. In March 2004 Mr Kennedy missed chancellor Gordon Brown's budget statement in the Commons, and a few days later was seen sweating and in generally poor condition when he spoke at a party conference in Southport. A gathering of senior advisers quickly followed, and it is reported in Mr Hurst's book that Mr Kennedy was directly asked whether he was an alcoholic and replied, after a pause: "Yes."

It was decided, notwithstanding the fact that a general election was likely to be only a year away, that he should be allowed privately - or secretly - to try to conquer his addiction. But in more than one sense the cork could not be forced back into the bottle. Mr Kennedy was certainly not at his best in the 2005 general election campaign, and the result disappointed his party. About six months later the writing was most definitely on the wall, and in a word it said: "Go!"

It has been repeatedly alleged that Sir Menzies Campbell and others engaged in a dishonourable plot to do Mr Kennedy down, but I think this is ludicrous and very unfair. They are far more vulnerable in my opinion to accusations of failing to confront Mr Kennedy earlier and of knowingly misleading the public or electorate. The efforts to stop the truth getting out did sometimes include threats of legal action against journalists and media organisations.

The main defence voiced yesterday is that his colleagues were keen to protect his privacy as he tried to get the better of his demons. But how could this not be a public as well as private matter? Excessive alcohol was obviously liable to cloud his judgment on very important national and international issues.

Might he, for example, have been less fundamentalist in opposing the Iraq war if he had been entirely sober? Quite possibly not, but it's a legitimate question.

Could he become the Lib Dems' leader again? Can he

really give up the drink? A 'yes' to the latter is necessary, but not sufficient.