Lisa McKenzie was prosecuted because somebody else put a sticker on a window. Let that sink in for a minute. Was the prosecution successful? No, because the British criminal system has thankfully not become a masterpiece of Orwellian satire, but the fact she was arrested in the first place – let alone ended up in a court – should frighten you, whatever your political persuasions. Our ancestors fought for our rights and freedoms, and at incalculable personal cost, too: it is an unforgivable betrayal to allow them to be chipped away.

McKenzie is a LSE academic and a member of Class War, an anarchist faction, who were protesting about London’s housing crisis. This crisis, by the way, is rather more serious than stickers on windows. Hundreds of thousands of Londoners are trapped on waiting lists for social housing, while an unregulated private rented sector with rip-off rents and a lack of security for tenants flourishes.

Rents are so unaffordable that one in four London households now claim housing benefit. The Mayor of London pledged to build “affordable housing”, which is an intriguing redefinition of the word “affordable” to mean “unaffordable” given it means up to 80% of market rents. McKenzie and her fellow protestors were protesting against so-called “poor doors”, which mean that tenants of supposedly affordable flats have to use separate entrances to luxury flat dwellers. Yes, in 21st century Britain.

Now, a disclaimer. I wrote an afterword for Lisa McKenzie’s excellent book Getting By: Estates, Class and Culture in Austerity Britain, which is undoubtedly enjoying a sales bounce thanks to the Metropolitan police and Crown Prosecution Service. I’m also an occasional target of Class War myself, who have picketed me with a banner featuring yours truly clutching a bottle of champagne (for a BBC sketch) and telling me to, well, “Fuck off back to Oxford”.

The circumstances of McKenzie’s farcical prosecution should alarm us. She was allegedly singled out by the police after they profiled her at a protest meeting. She was also prosecuted with a charge normally reserved for drug dealers and gangsters.

If only cases like this were one-offs. China’s dictatorship is now being feted by a government busily handing over British assets to it, while simultaneously calling the main opposition party a threat to national security and unpatriotic. A survivor of the Tiananmen Square massacre was “brutally manhandled”, as observers claimed, after trying to protest yesterday against China’s dictatorship, and then his home was raided by police. His wife has said they were left “traumatised” by the experience, claiming that “the police here in the UK are now doing the same things as in China”.

There’s the use of kettling, containing protesters for hours at a time, described by the UN Special Rapporteur on rights to freedom of assembly and association as “detrimental to the exercise of the right to freedom of peaceful assembly due to its indiscriminate and disproportionate number”. There’s the mass arrest of protesters and then the imposition of bail conditions banning them from attending peaceful demonstrations: as the Guardian uncovered at the end of 2014, 732 people suffered this fate since 2008 without facing any charges. As one solicitors’ firm puts it, “We are concerned that the use of mass arrest is being used as a way to deter protesters and allow biometric data to be gathered.”

The police are supposed to facilitate peaceful protest – it is a basic democratic right and freedom after all – but brutal tactics are often employed. The unlawful killing of Ian Tomlinson in 2009 was one extreme case, but I have witnessed indiscriminate uses of police batons myself. Even Countryside Alliance protesters suffered police violence in 2004. And then there’s the sinister use of undercover police officers, some of whom who had relationships and even children with activists while using false identities.

The treatment of Lisa McKenzie is so absurd it is tempting to turn it into one big joke. It isn’t. It’s about the basic democratic freedoms that our ancestors were compelled to fight for being fatally undermined. It is sinister, and to fail to speak out about it – whatever your personal beliefs – is a betrayal.