As a keen, green human rights lawyer I was once told "civil liberties are like good health. When you have them, you take them for granted. By the time you notice you are losing them, it's already too late. Once you have lost them completely, you would give anything to get them back".

I think of this remark whenever anyone questions how, in the middle of a recession, or faced with the real threat of a terrorist attack, it can be justifiable to spend time, energy and resources thinking about civil liberties.

One way of answering these doubts is with history. Try asking this. Q: When was the last time there was a global depression of unprecedented proportions? A: The 1930s. Q: What happened to civil liberties then? Go figure.

Or if you prefer a contemporary approach, pick a country where basic rights and freedoms are treated as irrelevant. It's easy to take for granted how remote an experience the arbitrary arrests of political opponents in Zimbabwe seem from the UK. Despite the recent attempts of some commentators to draw comparisons between the two countries (the outcry at the sudden arrest of Conservative MP Damian Green springs to mind), the exercise seems far-fetched. So far, there is little prospect of hundreds of years' worth of entrenching civil liberties in our unwritten but tenacious constitution being completely undone – and one of the reasons is that we enjoy such an active culture of effective scrutiny of our rights.

And it's not always the so-called "liberal conspiracists" doing the scrutinising. One of the most remarkable things about Lord Mansfield's famous judgment in the case of slave James Somersett in 1772 – declaring that slavery was something "so odious that nothing can be suffered to support it but positive law", a concept "not known to the laws of England" – was how quickly illiterate slaves throughout the British colonies demonstrated their ability to become up to speed with House of Lords case-law.

Slaves in the 18th century relied on habeas corpus – an ancient principle of English law dating back to at least the 13th century Magna Carta requiring detentions to be authorised by a court – which has been described as occupying a "mythical status" in the national psyche. More recently this fundamental right, updated by the "right to liberty" brought in by the Human Rights Act, has been successfully invoked by foreign terrorist suspects challenging the legality of the Anti-Terrorism Crime and Security Act 2001 – which allowed them to be detained indefinitely without trial.

It's easier, 300 later, to sympathise with the slaves so clearly on the right side of history, than with contemporary suspected terrorists. But it's worth remembering that there were many who, defending the slave trade back in the 18th century, argued that some people were more equal than others. The timeless thing about human rights is the underlying principle that all people – regardless of their popularity or anything else – are entitled to the same basic rights.

Which explains why it's not just the marginalised who find themselves suddenly attempting to become familiar with the law's impact on their civil liberties.

When he was arrested in November, Green would have needed to take a look at the Criminal Justice Act 2003 to understand how the police were able to take a sample of his DNA for indefinite storage on the national database, even without his consent.

Parents in Derby would have needed to resort to the Regulation of Investigative Powers Act 2000 to discover how their local council was able to invoke legal powers to record noise their children were making on their own property, and to ask whether the action was consistent with the act's stated intention of "gathering intelligence for the prevention of crime".

And the government of Iceland – not exactly a bog-standard terrorist suspect – was no doubt surprised to learn that its assets in Icelandic bank Landesbanki had been frozen under the Anti-Terrorism Crime and Security Act 2001, in spite of the fact that the act's stated purpose is to "cut off terrorist funding ... in the light of the new situation arising from the September 11 terrorist attacks".

Knowledge of the law can become essential in the most unlikely circumstances, and keeping up is not getting easier. This can be explained in large part by the ferocious legislating of New Labour, which has been creating new criminal offences at the rate of almost one for each day in office – recently estimated at 3,600 since coming into power. Even the legal profession, better placed than everyone else to stay abreast of new laws, is being swamped by what the UK's most senior judge Lord Phillips described earlier this month as a "ceaseless torrent of legislation".

In this climate there is no room for complacency. The UK may not yet be on the brink of descending into authoritarianism, but as the renowned human rights lawyer and Labour peer Baroness Helena Kennedy said recently, "the struggle against the abuse of power involves the struggle against forgetfulness".

Our new guide to key civil liberties and human rights legislation published since Labour came to power should be seen as part of that fight against complacency. It's a work in progress. Today – as liberty central, our new civil liberties site, launches – we are publishing 30 acts. Over the coming weeks and months we hope to build on that, adding key legislation past and upcoming. We also hope to expand our remit beyond the UK, taking in major pieces of legislation from the EU and the UN that also impact on our lives and laws. We hope you find it a useful resource. The struggle against forgetfulness starts here.