One day in 1962, the newly elected Member for West Lothian entered the tearoom of the House of Commons.

He got talking to an elderly gentleman who was friendly and very laconic. "What you owe the country, the House of Commons and the Labour Party is your best judgement."

That word of advice dispensed by Clement Attlee to Tam Dalyell encapsulated an ideal which the young MP turned into a dictum in a parliamentary career spanning 43 years.

Dalyell charts his relationship with home rule in a new book, The Question of Scotland: Devolution and After. Fast paced and bristling with anecdote and stories of politicians long forgotten, the Clement Attlee advice runs like a thread throughout the book as Dalyell exercises his best judgement in a career marked by principle without compromise.

He is of course best known for the West Lothian Question although the sobriquet was actually coined by Enoch Powell. "I bequeath to you the West Lothian Question" was one of Powell's last words to Dalyell when he paid the controversial Unionist a visit in hospital shortly before his death.

During the passage of Labour's Assembly legislation in the late 1970s, Dalyell harried the minister, John Smith, pointing out that he would be able to vote on health and education matters for Blackburn, Lancashire but not Blackburn, West Lothian in a post-devolved era.

"It is a question that cannot be asked enough," intoned Dalyell. "Yes it bloody well can," came the reply from Labour's lost prime minister.

Indeed Dalyell has some astonishing judgements on some of the key Labour figures on the long journey to home rule. There was no doubting the views of "Basso Profundo", as Harold Wilson called Willie Ross. The secretary of state for Scotland (1964-70 and 1974-76) thought nationalism should only be expressed at two venues: Hampden and Murrayfield.

When John Smith told Dalyell that he was "a pain in the arse" the West Lothian MP said Smith never challenged him on the substance of his constitutional critique. In his obituary of Smith in The Independent, Dalyell questioned whether he was really that much of a home ruler. Of one-time shadow Scottish secretary George Robertson, Dalyell has no doubts: He saw devolution as a means of stopping the SNP; it was no more than a political tactic.

Donald Dewar was a believer according to Dalyell although did not say much on the subject when MP for Aberdeen South (1966-70). Although Tam of The Binns did make efforts to befriend Dewar the First-Minister-in-waiting disliked Dalyell an emotion that was eventually reciprocated as Dalyell became exasperated with the man who helped stop '70s nationalism when he re-entered the Commons as the MP for Glasgow Garscadden in April 1978.

Tam Dalyell is extremely gracious, particularly towards political opponents and there are warm words for prominent Nationalists like Billy Wolfe, Winnie Ewing and Labour-turned-SNP politician Jim Sillars. Even talking to SNP members at his byelection count in 1962, he concluded that nationalism was a beast that would only be fully fed when there was a separate Scottish state. So started a long career in which he appeared a lone voice at times.

The harshest judgements are reserved for Labour colleagues. Many privately agreed with his critique but remained mute in pursuit of an easy life. Gordon Brown's dramatic intervention in the independence referendum in 2014 is dubbed an act of self-promotion and in a follow-up interview with STV News Dalyell effectively accuses the former prime minister of acting out of ego. "I am very angry with him."

Dalyell records that as his anti-devolution views became increasingly unfashionable moves were made to retire him early. But his cultivating of trade union leaders over many years proved useful in thwarting the ambitions of the apparatchiks out to behead him politically.

There can be no doubt that the Scottish Parliament is the settled will of the Scottish people. But the decades leading up to its creation were momentous and this is an important book in explaining the role of a man who fought against the tide.

The observations will also be important for academic scholars, many of whom rely on newspaper cuttings from yesteryear which in many respects merely reinforce the orthodoxy of the time. Here is a firsthand account of a parliamentarian who was there every step of the way.

A final thought. When I look at Holyrood and Westminster I see massed armies of parliamentarians who would be out of place saying boo to a goose. The activists turned researchers turned elected members owe their position to the institution of party and it is to party that they look when they exercise their judgement.

It is a dangerous trend that will allow governments to escape scrutiny and reduce important issues to the politics of the head count. Tam Dalyell's career, as this book demonstrates, stands as an antidote to all that is wrong with the lobby fodder culture which threatens the very notion of holding government to account.

The Question of Scotland: Devolution and After

Tam Dalyell

Birlinn, pp.176

Review by Bernard Ponsonby, STV's political editor. He joined the station in 1990 and became political editor in 2000. He has presented most election, by-election, and results programmes over the last quarter-century.