'Blonde assassin' who was behind Kennedy downfall

And yesterday she was dubbed the "blonde assassin" for her role in forcing Mr Kennedy to make a statement about his drinking problem.

Sources close to Mrs McAndrew smarted at the label, claiming she had never set out to betray her former boss.

She used contacts among senior Liberal Democrats to compile a report disclosing the damaging allegations about his alcohol problem and had even alerted his office about it ahead of broadcasting her scoop.

But in an act of revenge, Mr Kennedy scuppered her scoop by outing himself on television to rival broadcasters.

At a press conference, Mr Kennedy claimed that his battle with booze had plagued him for 18 months.

This is a statement that will probably be challenged by those in the know.

Mrs McAndrew witnessed Mr Kennedy's drinking first-hand, and in the two years ahead of the 2001 election she covered up his weakness.

When asked during a television interview why Mr Kennedy's breath often smelt of alcohol, she replied unconvincingly: "Charlie uses a breath freshener with alcohol in it."

Daisy Sampson - as she was known before marrying John McAndrew, who is now Sky's executive producer - entered the House of Commons as a researcher aged 19 before working as a freelance contributor to The House Magazine, Westminster's in-house publication, which she went on to edit.

It was here that she met Mr Kennedy. When, in 1999, he asked her to become his press secretary, she initially turned him down as she did not want to ruin their friendship. She eventually changed her mind.

"I wanted to find out whether stories were the result of cock-ups or conspiracies," she explained in a recent interview with the Mail on Sunday.

She said that the hardest part of her new post was "taking on a friend" while working for him.

"As a media adviser, I had to be his hardest critic. I had to tell him when his speech was rubbish, even when everyone else was being sycophantic to him. It was my job to put the boot in, and that was tough because he's a lovely man."

Despite their professed friendship, Mrs McAndrew did not invite Mr Kennedy to her wedding, although she had attended his.

She served as his spin doctor until after the 2001 election, when she moved on to a stint of broadcasting roles, including that of co-presenter on the BBC's The Daily Politics.

In one telling interview, she revealed that her trump card in getting stories was not getting as drunk as everyone else.

"I'd get all my best stories at party conferences at three in the morning, when everyone was propping up the bar, absolutely hammered," she said. "One of the hardest things was keeping up with everyone but not getting so drunk you couldn't remember the story the next day. I spent the whole time running to the loo to jot down notes in my pad."

Despite her competence as a broadcaster, eyebrows were raised in Westminster circles when she landed the job of chief political correspondent for ITV.

Speculation is now rife as to whether she promised her bosses scoops, or whether they exerted pressure on her to "turn over" her best contact.

Perhaps Mr Kennedy should have been worried long before this week's revelations: Mrs McAndrew once harboured ambitions to be a spy.

She only switched to journalism after finding out she would have to speak several languages fluently in espionage.

Mrs McAndrew said she reasoned: "Well, they [journalists] sometimes end up becoming spies."

And like spooks, they sometimes end up working for the other side.