Since returning to power as a majority government, free of the Liberal Democrats, the Conservatives have introduced a battery of measures to weaken the opposition and to limit accountability: the freedom of information act review, the planned reduction in the House of Lords' powers, the 19 per cent cut in public funding for opposition parties and the trade union bill.

In a speech tomorrow morning, Tom Watson, Labour's most vigorous champion of civil liberties, will take aim at this agenda. He will call on the Tories to abandon their FoI review, describing it as "a particularly egregious example of their determination to reverse the transparency Labour introduced."

"It doesn’t have the support of the public," he will say, "it is opposed by many of the organisations that are covered by FoI; it has been condemned by the Information Commissioner and slammed by a former head of the civil service. It’s a waste of taxpayers money and it’s time it was scrapped. The Freedom of Information Act works well. Labour would strengthen and extend it."

Watson will highlight the disparity between the Tories' actions and their past words in opposition and coalition.

The Tories used to talk up transparency, because it made them seem radical and modern. The 2010 Coalition agreement promised to 'throw open the doors of public bodies, to enable the public to hold politicians and public bodies to account”. This included a commitment to “extend the scope of the Freedom of Information Act to provide greater transparency'. It would be funny if it wasn’t so serious. Because now that he has a clear Tory majority, and five years in government under his belt, the Prime Minister is 'reviewing' the Freedom of Information Act with a view to making it significantly weaker, not stronger at all. As opposition leader he famously said 'Sunlight is the best disinfectant' and promised the Tories would 'bring the operation of Government out into the open'. As Prime Minister he is methodically closing all the doors and the shutters, drawing the blinds and the curtains, retreating to the shadows at the back of the national farmhouse. He wants to govern from the gloom in the old fashioned way, without the inconvenience of scrutiny, abandoning any hope of decency or trust. His response to the crisis in our health service has been to introduce an NHS news blackout. NHS England has confirmed that the weekly information bulletin, which was due to begin publication on Friday 11th December, will no longer include figures on four hour waits in emergency departments, the number of ambulances queueing outside hospitals, or operations cancelled at the last minute. He thinks we won’t like what they’re doing, so they’re going to stop telling us about it.

But rather than merely reciting the traditional arguments for FoI, Watson will make an original and innovative case for the necessity of civil liberties in an age of greater economic interventionism.

"There is another reason why we have to ensure checks and balances on excessive state power are hardwired into our democratic institutions and political culture. "It’s because changing economic realities will mean the state has to play a more enabling role in the generations to come. Let me explain what I mean. "The hour glass economy is going to hollow out middle class jobs over the next quarter of a century unless the state acts. The Bank of England's chief economist Andy Haldane said last month that the Bank's own research showed this to be the case. In my view, if we are to adapt to the massive social upheaval that the impact of technology and automation is going to have on our society, there will have to be a growing acceptance of new forms of state intervention. I'm not talking about the next election but the direction of travel over the next 30 years. Where there is a greater acceptance of the role of the state in market intervention, industrial strategy, economic planning and adaptation to climate change." If this happens, there will have to be far more safeguards to protect citizens from erosions of their individual liberty. Governments have to work at this because there will be an institutional pressure to ignore the impact of unchecked state power. You only have to see what technological power allows the government to do with the Investigatory Powers Bill. For left leaning governments, it is important to have a strand of discussion that specifically focuses on civil liberties. Left leaning political parties need to encourage internal debate about civil liberties.

Watson will also root his argument in philosophy, arguing that it is imperative for the left to reclaim the cause of personal liberty from the right. Far from being counterposed to equality, he will argue, the two values are mutually dependent.

We know all about the aspect of the socialist tradition which stretches back to Hegel and centres on equality of condition. For sure, that’s one of the two central strands of our philosophical inheritance. But I think we often forget on the British left that the other key strand of our tradition traces its roots back before Hegel, to Rousseau, and has as its founding principle not equality, but liberty. Because you can’t have one without the other. They are always and inextricably linked. It’s an interdependent bargain, a balance, with each side as important as the other. We need to have these debates with David Cameron secure in the knowledge that we own liberty just as much as he does, indeed more so. We don’t repudiate liberty as they try to portray us.

He will add: "These Thatcherites all worship Hobbes, because he was so cynical about the state, whereas it’s actually Locke and Rousseau who gave an equal place to liberty in their social contracts. Liberty is ours, not theirs. Our tradition is of liberty, a benevolent state AND equality.

"Though it’s the Hobbesians, paradoxically, on the right of the Conservative party who most often found common cause with the civil libertarian dissenters in the Blair to Miliband era. The challenge for both parties is to hot wire our tradition of liberty into the way we make policy today – in both parties and in government."

Finally, he will warn: "With this government we are moving to a new era of private government, where ministers know best. It's resonant of Harold Wilson's description of the then Conservative government as being run on the principles of the Edwardian Grouse Moor."

Many civil libertarians have never forgiven Labour for its attempted introduction of ID cards, 90-day detention and control orders. But Watson's thoughtful and principled speech should help his party win a hearing.