TAM Dalyell can sum up what has gone wrong with the House of Commons in his more than 40 years at Westminster in a single word which he spits out:"Thatcher."
It is clear that he regards her decade as prime minister as the worst time of his tenure as an MP. It is no accident that all his five expulsions from the Commons Chamber took place under her premiership.
And despite his more recent bitter disagreements with Tony Blair - most notably over the invasion of Iraq which he regards as the worst decision of his time as an MP, worse even than Scottish devolution which he once predicted would lead to the break-up of Britain - he still says he has a high regard for the current PM.
Surprisingly for someone who describes himself as "ancient Labour", the 71-year-old Father of the House of Commons even considers the 1997 election of the "New Labour’’ Government the high point of his time at Westminster.
He also claims to have no regrets about leaving in the next couple of years - well maybe just one, but more of that later.
Edinburgh-born Dalyell - married for 40 years to wife Kathleen and father to Gordon and Moira - says: "Things have changed hugely since 1962. Back then most of the MPs had fought in the war together and that made the place far less adversarial and people talked to each other much more. That was a good thing. The change came in with Thatcher.
"You were either ‘one of us’ or against her. For example Harold Macmillan and Alec Douglas-Hume and indeed Edward Heath would invariably invite some trade union leaders and some opposition politicians to Downing Street dinners, but that was something Thatcher didn’t do."
He adds: "Things have not improved. I’m afraid she set the tone of it. There is far more point-scoring now and I don’t think it’s a good thing."
As a result he believes the public opinion of politicians has fallen, albeit he says, in most cases unjustifiably. "We live in a much less reverential society. But I don’t think politicians are corrupt. I think there’s very little corruption. And I do think that the politicians of today are far, far abler people than those of 1962 - and they are more hard-working."
Not that Dalyell has ever flinched when it’s come to working hard on behalf of his constituents, or on any issue in which he holds a fervent belief - the sinking of the Argentinian ship the Belgrano and the West Lothian Question on the issue of Scottish devolution are just two of the issues which have made him a thorn in the side of countless politicians on all sides of the House over the years.
But Dalyell has always been a bit of a maverick. For someone who’s seen as a guiding light of the Labour left, Dalyell in fact started his political life as a Tory at Cambridge, where he was chairman of the university’s Conservative Association. He ended up at Cambridge after being educated at Eton, but as time went on he realised that the Conservative Party was not for him after all and, as shocking as it was for some of his privileged fellow graduates, a switch to Labour became inevitable. "It wasn’t so much that I changed, more that I should never have been a Tory," he admits.
After a stint as a trooper in the Royal Scots Greys for his national service, he began teaching at Bo’ness High. But he had begun making a name for himself in the Labour Party and, in 1962, got the call that he was being put forward for the vacant West Lothian seat following the death of John Taylor. With his Etonian accent, and the fact that he lived in one of Scotland’s stateliest homes, the Binns (although it’s been in the ownership of the National Trust for Scotland since he was 12), there were many who scoffed at the suggestion that he was someone who could understand the needs of the people in that area.
"There were a lot of people who said that," he recalls now. "And I was well aware of it. But I have held a weekly there ever since, my phone number is in the Edinburgh phone book and I think I have proved something here."
In the Commons he began to climb the slippery pole, but got into "terrible trouble" when he leaked a copy of a document containing evidence given to a select committee on a chemical warfare establishment at Porton Down in Wiltshire to a journalist. His action sparked a huge political row and triggered the Commons’ toughest disciplinary procedures. He was summoned before the privileges committee and then made to stand before the Speaker wearing a black cap - a process that had not been enacted for more than 30 years and never repeated since.
"There was a terrible shemozzle and they wanted to have a leak inquiry," he says. "I was bloody near to being expelled." Even now though he doesn’t believe his actions were wrong.
He was finally made a front-bench spokesman - for science - when Michael Foot became the Labour leader. But the onset of the Falklands war led to him voting against the whip and being sacked from the post. This came during his famous, or infamous, campaign against Margaret Thatcher over the sinking of the Belgrano.
It was a campaign that put Dalyell in the national spotlight and one that he continued to pursue relentlessly. He was also at the centre of intense controversy over the Lockerbie bombing, arguing that the Iranians, rather than the Libyans, were to blame.
Meanwhile, in the Scottish Labour Party, his persistent criticism of devolution was a continual problem. As the author of the celebrated West Lothian Question, he effectively raised the issue of why Scottish MPs at Westminster can vote on English domestic issues, such as education, whereas English MPs cannot vote on education in Scotland.
It’s an issue he still believes hasn’t been dealt with, but coyly only says: "My attitude has been that I had a lot to say but that I have not criticised the Scottish Parliament since it was set up on the grounds that we have it now and for everybody’s sake we’ve got to try to make it work."
On other "dreadful decisions" by governments in his time at Westminster, Dalyell is more forthcoming: "I think the bombing of Belgrade was a dreadful decision and the bombing of Afghanistan was a dreadful decision. We should have sent land forces, possibly, to Yugoslavia and Afghanistan under United Nations’ auspices but the bombing of Belgrade has just created chaos in Serbia."
Iraq has been the issue which has been exercising him most recently. "I think that the Iraq war was quite, quite wrong. Saddam Hussein was not a nice man but he wasn’t responsible for international terrorism. There was a connection between Saddam Hussein and al-Qaida and the connection was that on two occasions al-Qaida tried to assassinate Saddam."
He continues: "I never believed there were weapons of mass destruction. I went to Iraq in 1998 and I believed Tariq Aziz, and others, when he told me that any weapons they had of a biological nature had deteriorated and they hadn’t renewed them."
He adds: "In Iraq I think it’s likely to go on and on until the western forces withdraw. Then I don’t think it will descend into chaos. After western forces have withdrawn, I think we might find quite a sensible government emerging. Ironically, with the capture of Saddam, it has allowed a number of people who loathed Saddam nevertheless to take up, as they see it, the patriotic cause of getting the west out."
Turning back to how Parliament has improved and declined in his 40 years, he says: "What has improved is that MPs have become far more hard-working. I’m sure that the present generation are the best constituency MPs there have ever been. In some cases it detracts from their ability to look at wider issues but it shouldn’t.
"I don’t work harder now in my constituency than when I first came to the Commons because I have always worked hard in that I continue to have surgeries every week and I’ve been blessed with an extremely good local authority.
"After 40 years I shall miss representing my constituents. It has been wonderful to do that. Obviously I shall live in the constituency and do what I can to help my successor. But I won’t be breathing down their neck."
He has no doubt that the lowest point of his time at Westminster was the prime ministership of Margaret Thatcher: "One of the points about devolution was that she was so identified with being against it that very few people on the left could get a hearing, without appearing vulnerable to sharing her views.
"When she came to power in 1979, devolution was a dead duck. I think if there had been a normal prime minister in 1979 that it would not have surfaced. She did an immense amount of damage."
It was under her premiership that he saw himself repeatedly expelled from the Commons. "There were five altogether, twice on the Falklands and knowledge of the Peruvian peace proposals where I thought she lied about that. And she did, she had.
"And three times in relation to Westland. It was because of my insisting and saying she told a lie. I have no regrets about that. Look, she had. I wasn’t wrong."
The best moment in his career may come as a surprise to those who think he is just a member of the left-wing awkward squad. "I think the particular moment was the election of a Labour government in 1997. I don’t think Tony Blair has been a bad PM. I think it’s been a good government.
"My problem with Blair is two things. First of all he’s been too presidential and secondly this insistence on bombing Yugoslavia, bombing Afghanistan and being impatient about Iraq. He may have inherited that from the Thatcher years. The one lasting thought I have is that I am one of the very last MPs to have been in the services and to actually have fired guns."
As he contemplates a life without the Commons, he says: "I shall not regret leaving. Not at all. I’m just lucky to have been around in an interesting job for 40 years. I’ve enjoyed it."
Pushed further though, he does eventually admit to having one regret. "I do regret never being a minister. What I would have done would have been up to the prime minister. Michael Foot made me a shadow science minister and I believe Neil Kinnock would have made me a minister," he says, somewhat wistfully.
Then, almost mischievously as he heads off for yet another crunch meeting of the Parliamentary Labour Party on top-up university tuition fees, he adds: "I think if I had been a careerist, I would have operated very differently."