WHY do they do it?

Why do political leaders, even in Scotland, worship at the tawdry court of The Sun king Rupert Murdoch? What do they think they'll gain? Murdoch is the most toxic brand in British public life, his crude right-wing publications a byword for bent news and illegal practices such as phone hacking. Yet there he was, the "Dirty Digger" as Private Eye calls the boss of News International, calling into Bute House on Wednesday for a tete-a-tete with Alex Salmond, even as claims of a network of police corruption linked to The Sun were reverberating across the Leveson inquiry. And on the very day that James Murdoch resigned in disgrace from his post as chairman of NI. How many votes does Alex Salmond want to lose?

Of course the First Minister insists Murdoch was just there to talk about jobs as one of Scotland's leading employers. But if he thinks Scottish voters will believe that then he is out to lunch. Salmond also says that he made his views clear about Leveson and newspaper ethics. But this came rather hollow from a politician who had just leaked the date of the Scottish independence referendum – October 18 – to give the super soaraway Sunday Sun a front-page splash for its first edition.

Is that really the kind of behaviour we expect from our First Minister? That he sells his referendum for a sycophantic tweet from Rupert Murdoch, who called him Britain's "most brilliant politician" on Twitter. It's not even as if the Sunday Sun actually supported independence. It won't unless and until Murdoch becomes convinced that the referendum is a certainty. The Sun doesn't lead opinion – it follows it. Why don't politicians understand that.

The new Scottish Labour leader, Johann Lamont, made a spirited attempt to embarrass Salmond at First Minister's Questions. But it rebounded badly, not least because of Labour's own record of cosying up to Rupert. Salmond read out the guest list for Murdoch's summer champagne party, which included Ed Miliband and Ed Balls. He might also have reminded Lamont about Gordon Brown's wife Sarah's summer slumber party, whose guests included Rebekah Brooks when she was editor of The Sun – at the Labour prime minister's official residence at Chequers. Wonder if she brought her horse?

I vividly remember Labour leaking the date of the 2001 general election to the Sun – twice, because it was postponed over foot and mouth. Labour's reputation for obeisance to Murdoch is far more abject than anything the SNP has had time to acquire. In 1996, Tony Blair didn't just have tea with Rupert Murdoch. He flew halfway round the world to the Australian Hayman Island – apparently to reassure the press baron that he wasn't going to do anything to upset his media empire if he won the 1997 general election. The former Labour spin doctor, Lance Price, says that Rupert Murdoch was "the 24th member of Tony Blair's cabinet".

An entire generation of politicians has been corrupted – yes, corrupted – by association with this sinister oligarch, who should never have been allowed to acquire such monopolistic influence over the UK media. Murdoch owned The Sun, The News Of The World, The Times, Sky News and had his finger in other media pies.

Such cross-media ownership by a foreign national would never have been allowed in America, where they take press freedom rather more seriously than we do. Or France, or any other country with any concern for public ethics. Murdoch was, is, a cancer in British public life. He's a malignant presence at election time and at moments of national emergency. In the lead up to the Iraq invasion, Tony Blair spoke three times to Murdoch.

And of course the Tories have been just as supine before the Sun king. David Cameron's reputation as a political leader was severely, perhaps irreparably, damaged by his decision to appoint the former editor of the News of the World, Andy Coulson, as his communications director, even after Coulson had resigned over the phone hacking allegations (in 2007 Coulson denied any knowledge of phone hacking but resigned saying, as editor, he took "ultimate responsibility"). Why did Cameron do it? Because he felt this might give him influence over the Murdoch media empire. How can politicians be so naive? They don't control the Sun; the Sun controls them.

And of course the stench of real corruption now hangs heavy over the Metropolitan Police following the astonishing revelations from the Deputy Assistant Commissioner Sue Akers at the Leveson inquiry. Akers spoke candidly about what she called the "culture of illegal payments" to senior police officers and officials by The Sun. Of course, these remain allegations, but she's unlikely to have made them had she not been sure of her ground. For this is infinitely worse than the hacking of celebrities' mobile phones. If hundreds of thousands of pounds really have been handed to police officers, or their conduits, to secure stories, then the integrity of the police will have suffered an even greater blow than that suffered by MPs following the revelations about their expenses.

Just think of it: police actually handing criminal intelligence for money to an outside organisation. Selling confidential information gathered through their privileged position as officers of the law who have the power to question any citizen suspected of any crime. This is truly shocking – the Leveson inquiry has inadvertently uncovered one of the biggest scandals in police history. The public will conclude that this explains why the police were so reluctant to investigate the phone-hacking scandal in the first place. They didn't want to bite the hand that fed them.

But why did the police feel they could act this way? It was reckless beyond belief, and apparently sanctioned, or condoned, at the highest level. Perhaps because the police saw that politicians were already hand in glove with the Murdoch empire and believed that this was just how things were in the "real world". They believed that Murdoch was indeed above the law, a sponsor of government, confidant of prime ministers, immunised from prosecution by virtue of his constitutional role as the man who decides who is suitable to win British general elections. Truly, we live in the Murdoch State.

And now we even have our own Scottish First Minister worming his way into Rupert Murdoch's unsavoury inner circle, sending him cosy notes and free tickets, meeting his agents 26 times since 2007. Trying to win favours from Murdoch's disreputable rags. Politicians always excuse this kind of ingratiating behaviour on the grounds that they have to keep the press on side; it's just how things are. Well, the First Minister of Scotland needs to be reminded that this is not how things are here. Salmond should disown Rupert Murdoch if he doesn't want to hear Scottish voters saying: "Ach, politicians. They're all the same."