Tom Watson has become a heroic pursuer of the truth, hunting down the bullies. The Labour MP for West Bromwich East has spent the past few years trying to unearth the crimes and cover-ups by those involved in phone hacking. Now, at blistering speed, he has given the fullest account yet of the sordid saga. Dial M for Murdoch plays on the Hitchcock theme to good effect: The title could equally have borrowed references from The Godfather, but that would have been too obvious. Last year, during the otherwise limp questioning by the Commons culture, media and sport committee of the Murdochs, Watson suggested that theirs was a mafia clan. Watson is at centre stage in the narrative, the caped crusader. This sits uneasily for two reasons. My lesser concern is stylistic. It seems strange for the protagonist to be described in the third person in an account he half wrote (his co-author, Martin Hickman, is a journalist at The Independent). Also readers should be reminded that Watson\'s conversion to the cause of ethics is somewhat belated. During the Labour government, he was one of Gordon Brown\'s most loyal boot boys, doing the necessaries on anyone who stood in the way of his hapless boss, including Tony Blair. Everyone is entitled to change; to see public life as more than adherence to a tribe. Watson\'s commitment to rooting out wrongdoers at News International has been staunch. He began fighting the fight long before it became fashionable and safe to do so. The book does not possess killer revelations. Perhaps that was too much to ask, because of the plethora of judicial and parliamentary inquiries and police investigations that are designed to do so, and have the power to subpoena witnesses and extract evidence. But as a compendium, as a charge sheet, this is a gripping account, particularly for the growing army of Leveson inquiry junkies. Watson and Hickman chart in detail the political and commercial calculations that underpinned editorial decisions at NI. When it came to blagging information about an early girlfriend of John Major\'s, no problem. But when it came to revelations about a friendship between a 22-year-old George Osborne and a dominatrix, the word went out to cover the story but to cast it in a sympathetic light. It was all about doing favours, and expecting favours in return — a point seemingly not lost on Jeremy Hunt, the culture secretary. The collusion was extraordinary, as was the criminality. The authors show how senior figures in the police turned a blind eye even when confronted with compelling information about possible criminality high up in the Murdoch empire. Police chiefs even went in to bat for the Murdochs against The Guardian, to \"lobby [the paper] to drop its hostile coverage\", they write. Anyone who got in the way of NI and its business interests was encouraged to lay off. Key figures were either wooed (such as the Alexander and Evgeny Lebedev, the owners of The Independent and Evening Standard), or threatened. If blandishments did not work, they could be mercilessly attacked in one of Murdoch\'s titles. Watson reveals that he was approached on several occasions and offered deals to stop his investigations. When he refused, they went for him. This doughty campaigner has been spectacularly vindicated. But for a book such as this to be regarded as the definitive work, it needed to analyse why two generations of politicians and public servants prostrated themselves at the Murdochs\' feet. Watson reminds readers that even as late as last year, the entire Labour leadership paid homage at the Murdochs\' summer party, including Ed Miliband, who has since tried to distance himself. Intriguingly, Watson describes how Blair becoming godfather to Rupert\'s latest child was supposed to remain a closely guarded secret. For some, such as Brown, the motive for cosying up to Murdoch was fear. In Blair\'s case, it seems genuine affection. Now the heat is rightly on David Cameron and the cabinet. But readers deserve to understand better why the Labour government allowed itself to become a subsidiary of NI, each policy cross-checked for approval. Watson makes a stab at some answers, but his conclusions are confined to 13 pages. He provides a rogues\' gallery, including names and organisations that are rarely mentioned as moral accomplices: \"the London mayor who did not demand action from his police force, the Queen\'s solicitors who knowingly continued to act for a lying corporation\" and, somewhat bizarrely, \"the BBC executives who failed to devote resource to a national scandal\". \"In the end, this story is about corruption by power,\" he notes, before adding, vividly of the Murdochs: \"From the criminal underworld to the headquarters of London\'s police force, from the decks of yachts in the Mediterranean to farmhouses in the Cotswolds and the deep-carpeted rooms of Downing Street, they had spun an invisible web of connections and corruption.\" The law of the playground states that the bully survives only if he is indulged. That surely is the greater crime, and that is laid at the politicians\' door.