Just as we were preparing to close up our shop on Saturday evening, about a dozen men invaded Bookmarks bookshop in central London and started knocking over displays and shouting at staff. One was wearing a Donald Trump mask, others wore baseball caps saying Make Britain Great Again. One wore a union jack as a cape. They zeroed in on books about Islamophobia, and ripped up copies of an anti-racist magazine.

Thankfully nobody was hurt and damage to the shop wasn’t extensive, but the message this attack sends is chilling. This was a group of so-called alt-right protesters who decided that a socialist bookshop, which stocks radical literature and working-class history titles and provides stalls for national trade union conferences, was a legitimate target for violence.

And Bookmarks is not alone here. In April, Gay’s the Word, the renowned LGBT+ bookshop up the road from us in Bloomsbury, central London, had its windows smashed. Again, no one was hurt, and there’s no reason to think the attacks are related, but they certainly take place in an atmosphere in which racists, bigots and the far right in general feel emboldened.

Donald Trump’s election as United States president has released a feeling among some on the hard right that it’s now OK to say out loud things that had been made unacceptable – and that feeling can easily turn into violence, as we found on Saturday.

But it’s not just Trump. Here in Britain, we’ve seen the emergence of organisations such as the “anti-extremist” Football Lads Alliance, which has targeted Muslims and prominent black figures such as MP Diane Abbott. The movement that has gathered around Tommy Robinson, the founder of the far-right English Defence League, is another recent example.

And these movements are growing in a fertile ground prepared by Theresa May’s “hostile environment” for migrants – which, as we’ve seen, poisons our whole society by reopening older racisms such as those faced by the Windrush generation 70 years ago.

Thankfully it’s not all going in the same direction. When Trump visited Britain last month we saw enormous demonstrations. London had a carnival atmosphere as hundreds of thousands marched for women’s rights, against homophobia and transphobia, against racism, climate change and war.

You may burn my books … but the ideas those books contain have passed through millions of channels and will go on Helen Keller

Following this weekend’s attack, Bookmarks has received thousands of messages of support from around the world. Since we reopened this morning the phone has been ringing off the hook with people offering solidarity; visitors have dropped off cards and donations. We’ve had authors and other prominent figures contacting us to offer to speak or read at our solidarity day this coming Saturday.

It is easy to see why. When the far right starts attacking books, alarm bells ring for anyone who wants to live in a democratic society. In May 1933 the German student union, a Nazi organisation, initiated the mass public burning of books in an attempt to “purify” society and rid it of “un-German” influences. Tens of thousands of volumes were hauled from libraries and archives and burned in public squares.

Among the first to be burned were books by socialists and communists such as Karl Marx, Rosa Luxemburg, Friedrich Engels and Bertolt Brecht, and novelists including John Dos Passos, Jack London, Maxim Gorky, Franz Kafka and Upton Sinclair. Books by all of these authors can be found on the shelves of Bookmarks today.

It was notable that one of the titles the attackers singled out on Saturday was The Jewish Question by Abram Leon – written shortly before the Jewish author was murdered by the Nazis in Auschwitz in 1944. The men who attacked Bookmarks grabbed it from the shelf and threw it across the shop.

In response to the Nazi book burnings, the American author and activist Helen Keller wrote: “You may burn my books and the books of the best minds in Europe, but the ideas those books contain have passed through millions of channels and will go on.”

The fantastic response Bookmarks has received since Saturday lets us know that we’re not alone – and that people understand the value of independent bookshops in a world dominated by big business. We are grateful to everyone who has supported us: it shows that we can’t be cowed by the forces of intolerance and the far right. The most important outcome will be if more people learn the true meaning of solidarity – that an attack on one is an attack on all.

• David Gilchrist is the manager of Bookmarks