The alleys of the refugee camp are narrow but neat, and although the walls are high, there are flowers trailing over the tops. The women hanging out freshly -washed clothes have flowing hair caught back in white handkerchiefs, and the boys working in the grocer’s shop are happy and hard-working as they toss fat watermelons to pile up in front of the store.

Mustafa Abu Ali’s 1974 film They Do Not Exist (Laysa Lahum Wujud in the original Arabic) opens with this idyllic view of the Nabatia Palestinian refugee camp in Lebanon.

The title itself is a statement of resistance – a rejection of 1970s Israeli claims that there were no such people as the Palestinians, and of the 19th century Zionist notion that Palestine was a “land without a people”.

The ordinary folk of Nabatia, depicted in the camp’s last days, embody the slogan that “to exist is to resist”. The very normality of their daily lives is a signal of their strength and steadfastness.

But 1974 was the heyday of the Palestinian armed struggle, and the idyllic image couldn’t last.

Indiscriminate Israeli bombing in May and June of that year destroyed much of Nabatia, killing many civilians and driving the refugees into a second flight to Ein el-Hilweh camp. Much of the rest of the film is taken up with testimonies of witnesses to the Israeli attacks, and defiant survivors lamenting their loved ones.

These might seem like familiar tropes from the many films depicting the Palestinian plight that have been made since. But in 1974 Mustafa Abu Ali’s film was something new.

Wanting to document his people’s struggle, he and comrades such as Sulafa Jadallah, Hani Jawhariya and Khadija Abu Ali, had only recently founded the PLO’s Palestine Film Unit.

Between 1968 and 1982 the unit made over 60 films, with the support of global names in cinema such as Jean-Luc Godard. Some productions – like They Do Not Exist – won prizes at international festivals, and the unit’s work was credited with helping to shift the world’s perception of the Palestinian people from one of helpless refugees to that of a nation in struggle.

The unit was enmeshed in the wider artistic work of the resistance, with links to the PLO’s culture wing under the directorship of renowned painter Ismail Shammout. Although the unit produced mainly documentaries, it also shot an adaptation of Return to Haifa, the short story by Ghassan Kanafani, the assassinated spokesman for the Popular Front for the Liberation of Palestine (PFLP).

Perhaps the most poignant reminder of the place of Palestinian film-makers in the struggle is the danger they faced. Hani Jawhariya was killed by a bomb during the Lebanese civil war, Umar Mukhtar and Mu’ti Ibrahim were shot by Israeli soldiers in south Lebanon in 1978, and Sulafa Jadallah was severely injured.

After Israel’s 1982 invasion of Lebanon and the flight of the PLO from Beirut, many of the Palestine Film Unit’s works were destroyed, stolen or scattered. But slowly, some have come to light.

In the case of They Do Not Exist, much of the credit goes to filmmaker Annemarie Jacir, who hunted down the old reels for a Palestinian film festival in Jerusalem in 2003. She also managed to bring Mustafa Abu Ali to the screening, the first time he had seen his film on Palestinian soil, and his first view of it in two decades.

Now, They Do Not Exist is available on YouTube and is garnering thousands of viewers. In this age of glitzy videos, carefully optimised for smartphone viewing, what is attracting watchers to a short, black-and-white, subtitled movie, probably made before they were born?

Firstly, perhaps, is the fact that, despite growing awareness of Palestine in Europe and even the US, there are still plenty of high-profile voices who deny Palestinian rights and even their existence – notorious recent examples include 2012 American presidential candidates Newt Gingrich and Rick Santorum.

In a contemporary setting, the strength of They Do Not Exist’s message is redoubled. Not only is the film’s original aim – asserting the existence of the Palestinian people – still relevant, but its own status as a historical artefact multiplies the force of that aim.

It is a reminder that resisting the Israeli effacement of the Palestinians is an act with a long, proud history.

Secondly, unlike many contemporary films, They Do Not Exist isn’t just about Palestine. It explicitly links the Palestinian cause to other anti-imperialist struggles – Mozambique, South Africa, Vietnam and Native Americans. At a time when protesters in the West Bank and Baltimore are openly identifying with one another, this 41-year-old film speaks to a new generation of politically aware youth.

Finally, and perhaps most importantly, I think the interest in They Do Not Exist points to a thirst for knowledge among those who have come to the issue of Palestine through the horrors of news footage from Gaza or of reports of human rights abuses.

Current events might stir anger and sympathy, but they are only a snapshot in the Palestinian story. The fascination aroused by They Do Not Exist isn’t a lone phenomenon, I would argue.

Numerous Palestinian autobiographies, diaries and memoirs have been translated into English and published in the last few years.

My own biography of fighter Leila Khaled also attracted more interest than I, or the publishers, ever expected. That includes editions translated into Turkish, Danish, Bahasa Indonesian and – the ultimate accolade – Arabic. The PFLP may now be a spent force, but people still want to comprehend the background to today’s situation.

Young people are often criticised for not being interested in history, but those engaged on the issue of Palestine do, it seems, look to books and films from and about the past to deepen their knowledge.

And a film like They Do Not Exist doesn’t just give them facts; as an artefact from the struggle, its very existence is an important fact in itself.

That, I think, is why having films like They Do Not Exist available on the internet is so important. When they appear at film festivals and activist events the numbers of people reached are tiny compared to the knowledge they can convey online. The soundtrack may be crackly and the pictures grainy, but they are a voice from and about the past, and nothing can replace that.

Sarah Irving is the author of a biography of Leila Khaled and a doctorate researcher at the University of Edinburgh. They Do Not Exist can be found on YouTube using the search “Laysa lahum wujud”.