Chris Mullin: 'I can't believe Ed is that naïve' He became a junior minister under Tony Blair, scaling "the foothills of power" before being dropped - then emerged quite unexpectedly as one of the great diarists of our times, a waspish, witty and sometimes wise observer of politics and the secret lives of politicians. Mr Mullin knows all about the relationship between his party and the unions, having written about it in his 1982 novel A Very British Coup, recently filmed as Secret State. "The unions are their own worst enemies, very often," he says, remembering the strike-filled Seventies, when he was a journalist. They were very irresponsible. The union Unite is now accused of trying to rig the vote for a new Labour candidate in Falkirk and the police have been called in. The leader has also declared an end to the system under which thousands of trade unionists are automatically enrolled as party members. Mr Miliband believes the union grip on Labour will be loosened and at the same time many of these default members will become more committed to the party. "I hope he's right," says Mr Mullin. I think it will lead to a financial crisis. We had one a few years ago. A very serious one. The banks almost foreclosed on us. The loss will be severe and it will affect the capacity of the opposition party to win an election, or even to mount an effective challenge. It seems foolhardy to me. But who am I? Who indeed? A small, slender 65-year-old man in a Panama hat, wearing chinos and an open-necked shirt. There is an air of mischief about him, but Mr Mullin is a serious, experienced political campaigner. It was his investigation that helped free the Birmingham Six after years of unjust imprisonment. "Unions are the reason we have redundancy pay, sickness pay, paid holidays and all the other things we quaintly associate with civilisation," he says, defending their automatic link with the party. It's not a difficult case to make, and I wish somebody would make it. If the Labour leader isn't going to do that, then who will? Well, there's a very good point. They have been scared by this business in Falkirk, which has been blown up out of all proportion. Of course it's a bad thing, it should be sorted, but it's not the end of the world. The Right have been doing that sort of thing for years. His eyes light up when I tell him that Tony Blair has now intervened in the dispute to say that Ed Miliband's plan is bold and brave. Ha! There is a phrase in the Civil Service. When officials say, 'That's a very brave move, minister," they mean you are completely bonkers." He chuckles. Blair never did it, did he? For all his anxiety to put a little distance between himself and the union barons. Mr Blair dominates the diaries, being referred to throughout as The Man. Was Mr Mullin dazzled by him? His ability was dazzling. He was astoundingly good. There is one entry from 2010 that records "nervousness" at The Man's "considerable commercial interests" after leaving office. As an MP, Mr Mullin represented one of the "less prosperous" parts of the country. The most notable expenses claim he ever made was a £45 television licence, for a black and white set. It worked perfectly well. So how does he feel about the former Labour prime minister becoming a permanently tanned jet-setting multi-millionaire? The rush for the boardroom immediately after leaving office used to be a Tory phenomenon. Now it has become a Labour one, too. That answer is a little too easy. He says it's not his job to defend Mr Blair, but he can't resist. In mitigation, he employs 130 people in four charitable foundations. I think you'll find that to pay the salaries of all those people he has to keep moving around in circles ever faster. He looks permanently jet-lagged, don't you think? So he doesn't feel betrayed? No, I don't. What I regret about Blair is that he allied us umbilically to the worst American president of my lifetime. But I can say with my hand on my heart that the lives of the people I represented improved immeasurably during the 13 years we were in power. Does he miss Parliament, after leaving in 2010? Surprisingly, no. It's always better to go while people are asking why, rather than when. Mr Mullin still lives in Sunderland with his wife Ngoc, whom he met in Vietnam. When their second daughter finishes A-levels, they will move to a cottage with a walled garden in a valley west of Alnwick. I have achieved my lifetime ambition, to own such a place. All that remains is to live long enough to enjoy it. He lectures, chairs a Heritage Lottery committee, sits on charitable trusts and continues to engage with politics. The diaries saved me. The pleasant surprise was to discover that the political meeting is not dead. It has simply transferred to the literary festival. The stars of this circuit include a small band of former politicians who have discovered the ability to charm audiences of all political stripes. Tony Benn showed the way; Ann Widdecombe is another. Chris Mullin is a natural, having cultivated friendships with, improbably enough, erstwhile opponents such as Sir John Major. "I think there have always been politicians of integrity, just as there have always been some that have not got integrity, but they are not confined to any one particular party," he says. I have always had friendships across the divide. The great beauty of living in a democracy is that we are not, ultimately, trying to kill each other.