It's best to highlight this government's attack on liberty rights and privacy with cases where people have been penalised by the government or its agencies when they've done nothing wrong. But occasionally it is worth looking at the legislative process because it is the failure of democratic and protective instincts in parliament that are at the root of the crisis of liberty.

I make no apology for reproducing part of an editorial about the Climate Change Act from the subscriber magazine Criminal Law Week. It's arcane and it's dry, but it explains exactly what's going on.

This act is one of the new breed of acts, vast swathes of which exist only in the hypothetic, to be enacted by secondary legislation behind the scenes, with no or minimal parliamentary scrutiny. What parliament has effectively done is issue the government with a blank cheque in relation to climate change to make provision as it sees fit be that in respect of the criminalisation of the private citizen for failing to leave his rubbish out at the right time or in the right manner, or the penalisation of companies for giving their customers plastic carrier bags (13 pages of an act of parliament being devoted to this topic!). It is difficult to see how parliament could consider such a lack of transparency acceptable.

If you're looking for an answer to the question – how does Labour make so much law without anyone noticing? – and if you want to know how 3,000 new offences have been created, over a third of which carry prison sentences, then you are half way there. The shocking abuse of secondary legislation, usually referred to by the term "statutory instruments", is one of the scandals of our time.

Statutory instruments – ministerial diktats by any other name – are a way of making sure that little is debated or scrutinised by MPs. With their increasing use, power passes from the chamber of the House of Commons and parliamentary committees to ministers and ultimately to senior civil servants, a naturally undemocratic group who think of the public as an awkward managerial problem.

The provisions, which are inserted in a bill and allow the government to amend or repeal the legislation without debate are known as Henry VIII clauses. With good reason: they were named after Henry VIII's Statute of Proclamation of 1539, which gave him the power to make law by proclamation.

There is shameless honesty about this name. Although today there is theoretically a process of scrutiny, research by Richard Cracknell says most statutory instruments are, in practice, not debated. Of those that are, the majority are discussed not on the floor of the House of Commons but in a standing committee, after which they are reported to the House and voted on without any further debate.

The crucial point is that the trend is against debate and scrutiny in parliament. Cracknel's figures show that the number of acts passed is in decline over the last 30-40 years, while the number of statutory instruments has seen a sharp increase. From around 2,000 a year until the late 1980s to around double that now.

This pattern started under the Conservatives but it took off with Labour. "While the number of acts has been declining over the last four decades," writes Cracknell, "the number of pages of acts has tended to increase. Statutory instruments have grown in number and in terms of the total number of pages."

MPs either have no power to debate and scrutinise legislation, or there are so many pages of it that proper scrutiny is made impossible.

That is why parliament has lost so much power to the executive; that is why so many people have the vague feeling that law is being made without debate – pretty much in the manner of a syphilitic 16th century tyrant.

The Conservative MP Edward Garnier told me, "This is legislation made for the convenience of the government and its civil servants, which is wholly impossible to scrutinise in the Commons. The last few criminal justice bills, eg the Criminal Justice and Immigration Act 2008, the Offender Management Act 2007, the Identity Cards Act 2006, are all terrible examples of 'Christmas tree' bills on to which the government hangs anything that comes to mind and which vaguely fits into some power given a minister by the act."

Parliament First, an all party group of MPs headed by Mark Fisher, one of the leading democratic voices on the government benches, reported six years ago that parliament was failing "in its political duty to hold the government to account."

Fisher wrote then that while parliament was the main check and balance on the government, scrutinising and amending legislation, monitoring its actions and providing a public forum for debate, "in practice it has allowed itself to be driven to the margin".

I fully appreciate that statutory instruments are dull stuff for a blog but that is perhaps the reason why this vitally important story is so little understood.

Cracknells's figures show that secondary legislation has doubled in the last two decades. This fact together with the pages of uncharted opportunity in the Climate Change Act for ministers to issue hundreds of decrees should be enough to persuade us that we cannot hope to sustain our democracy if parliament is not reformed, modernised and made properly accountable to our elected representatives.

The Guardian is the media partner for The Convention on Modern Liberty, taking place on Saturday February 28 2009, which will debate these and other issues. You can buy tickets here