Michael Dobbs, bestselling author of House of Cards and former aide to Margaret Thatcher and John Major, has been described as the spin doctor of his generation. As his new novel, Churchill's Hour, is published, he talks to Hannah Stephenson about his role averting political scandals.

BEST-SELLING author Michael Dobbs knows a thing or two about politics. After all, he was a key aide to both Margaret Thatcher and John Major during their Downing Street years and is a former deputy chairman of the Conservative Party.

He based his hit first novel, House Of Cards, featuring the villainous Francis Urquhart (played by Ian Richardson in the award-winning TV series), on his own experiences of politicians. So, he knows a lot about skeletons in cupboards.

Indeed, the 56-year-old has been described as the spin doctor of his generation, having also been deputy chairman of Saatchi & Saatchi. And he admits there were many times when he had to protect indiscreet politicians from the press.

''In the 1980s, when I was chief of staff, I was the party's chief 'bonkbuster', with responsibility for dealing with these problems before they hit the newspapers,'' he confesses.

''There were many occasions when there was potentially a real problem. My job was to make sure that the scandal didn't erupt. It might have been a Boris Johnson-type situation, where the newspapers thought they had a story about somebody's private life and were pursuing it vigorously and we had to decide what to do with it.

''Nine times out of ten the story would only come out if the politician did something particularly stupid under pressure from a newspaper.''

Ironically, he says he never knew about the now well-publicised affair between John Major and Edwina Currie (which ended before Major became Prime Minister).

''I lay my hand on my heart and say that I did not know,'' he laughs.

He recalls that he once went to interview Lord Callaghan for research purposes and asked if it would be possible for a Prime Minister to have an affair.

'''No,' he said. 'It's simply not possible. It's not as if you can go round to her place for a quiet evening, with three cars full of bodyguards. As Prime Minister, you can never get away with checking into a hotel as Mr and Mrs Smith.

"And Number 10 is no good at all because the front door is going backwards and forwards morning, noon and night, with people coming and going'.

'The next day I wrote to John Major and mentioned that Lord Callaghan had told me that a prime minister getting into trouble with a woman isn't possible any more.

''John wrote back and said, 'He's right - there are so many people to see, documents to read, letters to sign, there simply isn't enough time. And even if there were, I'd much prefer a good game of cricket'.''

Michael firmly believes that in the vast majority of cases, the private lives of politicians should have no bearing on their political career. He dismisses the argument that the moral behaviour of MPs has an influence on what the general public finds acceptable.

''The British public are actually much more sensible, and get a better balance on these things, than headline writers,'' he says.

''If you go back over history, you will find that our greatest leaders have always been people with flawed private lives. It seems to be a repetitive pattern.

''Perhaps it is that men and women with political passions, who have the drive and the energy to survive and succeed in the difficult world of politics, have passions and drive in their private lives too. These often lead them astray.

''I don't think that we get a better quality of political leadership in this country by expecting our political leaders all to be angels. Normally, you find that those who have made no mistakes are simply those who have done nothing.''

He laments that politics, and more specifically politicians, are bland today compared with 20 years ago, and describes Tony Blair as ''George Bush's poodle''.

''Nowadays, the party machinery is in such control of MPs,'' he laments. ''Candidates and politicians sadly begin to look the same, which is why people like Boris Johnson stand out. Even Ken Livingstone stands out.

''Why did Ken Livingstone become Mayor of London? Not because people thought his policies were great, but because he stuck two fingers up at the Establishment and said, 'I'm my own man'.''

Michael's fascination with colourful politicians has led him to write the third in a series of novels about Winston Churchill.

Churchill's Hour is set in 1941, when the controversial British Prime Minister sets out to persuade America to join the war. The novel questions whether Churchill could have prevented the attack on Pearl Harbour by warning the United States in time to avert the Japanese onslaught.

''The more I get into the character of Churchill, the more extraordinary, colourful and contradictory it becomes. He made huge mistakes and had lots of faults,'' says Michael.

It's a well-written fictional tale, based on factual historic events, and his depiction of Churchill's character is both entertaining and insightful. It also shows how the leader's loyalty towards the cause affected his personal life, and threatened to rip apart his family.

But then, Michael knows only too well how politics can affect your personal life. He quit, but not before it tore apart his marriage to his first wife, Amanda, a devout Buddhist who changed her name to o-Sel Nyima and moved to America.

''I would spend days away from home,'' he recalls, ''dashing around the country, coming home exhausted and not having time for the family.

"It contributed very strongly to the break-up of my marriage. The trouble is that at the time you don't realise it.''

They had two sons, and he suddenly found himself a single parent.

''I did the school runs, sewing on the labels, cooking appallingly. It was desperately hard, but I wouldn't change a thing. I learned so much about myself. It changed me as a person for the better. It forced me to have time for other people. And I'm much closer to my boys than I otherwise might have been.''

He has remained on friendly terms with his ex-wife, and the boys see her several times a year. Michael has also remarried, to Rachel, who also has two boys. The family all live in a 300-year-old house on the Chalk Downs outside Salisbury.

The author's fixation with Churchill remains, and he's currently working on another book about the leader, set in 1945. The film rights to the Churchill novels have been bought by Columbia, and Michael would like to see Anthony Hopkins in the role.

He probably holds more affection for Churchill than he ever did for his formidable former boss, Baroness Thatcher, and admits that they have not kept in touch.

''Maggie and I never had a close personal relationship. I don't think we ever felt particularly comfortable in each other's company. I was probably terrified of her!''

* Churchill's Hour by Michael Dobbs (HarperCollins £17.99).