Sarah Slade watches We Are Many – a new documentary about popular opposition to the Iraq war – and she can’t help noticing what gets left out.

The title for We Are Many was taken from Shelley’s Masque of Anarchy, a poem written in protest at the Peterloo Massacre of 1819, when hundreds of unarmed protesters were attacked by government troops at a political meeting in Manchester.  While the event itself was considered a noble failure at the time, (universal suffrage didn’t happen for another 100 years)  the idea of non-violent protest in the face of  brutal authority went global, helped along by Shelley, Henry David Thoreau and others. Non-violent action was adopted by liberation movements around the world during the 20th century, and played a significant part in the collapse of empires.

We Are Many takes as its starting point another noble failure, the anti-war movement that sprang up to protest against the second Iraq War of 2003-2011. Though millions marched around the world in a massive, coordinated protest, the invasion of Iraq still went ahead, spearheaded by the US and UK governments. Yet the film argues that the global demonstration directly inspired the Arab Spring of 2013, where the dictatorships of Tunisia, Egypt and Libya fell in quick succession to a mass democracy movement that started in the streets of their capital cities.

It’s a beguiling argument, attractive to so many of us that shuffled around our capital city on that damp, chilly February afternoon. Demonstrations in London tend to take a standard form: meet your group at a pre-agreed point, hoist the banner, walk around the city centre shouting slogans (usually variations of “What do we want?” “[Insert cause here]” “When do we want it?” “Now!!”), chat to a bored copper or two, listen to the speeches in either Trafalgar Square or Hyde Park if you can be bothered then wander off in search of a cup of tea and the bus home, feeling that you had done something but knowing that not much would change.

The difference with the 15 Feb 2003 demonstration is that it was huge; I mean really really big. Nearly a million people marching through London, then several millions more  marching in cities around the world in a massive, global plea to the US and UK governments to halt the projected invasion of Iraq. I remember shuffling past Cambridge Circus and seeing the cast of Les Miserables hanging out of the windows of the Palace Theatre, cheering and waving. There were whole families who had never protested before and there they were, out on the streets, imploring the government to think again. Surely they had to listen?

Yet they didn’t.

The strongest aspect of the film is the build-up to the global demonstrations.  Various conflicting narratives are gathered and formed into a coherent timeline that starts with the September 11 2001 bombings, weaving in the US government’s attempts to associate the Al-Qaeda bombers with Iraq and the downright lies that were told to secure international backing for an invasion of Iraq. Alongside the activists from around the world, the director, Amir Amirani, also features interviews with government advisers such as Lawrence Wilkerson, former chief of staff for Colin Powell when he was the US Secretary of State for Defence. From the UK he includes the likes of Clare Short, David Blunkett and Lord Falconer, all members of the cabinet at the time.  While there are few surprises for anybody who followed the events closely at the time, there is a perverse gratification in watching the people who told us that we were wrong at the time finally admitting that no, there wasn’t much evidence for weapons of mass destruction and yes, the whole premise for invading Iraq was at best, specious and at worst downright dishonest.  Maybe it was a condition of their appearing in the film, but Blunkett, Short and Falconer all get off remarkably lightly with admitting that maybe the information they based their decision on wasn’t 100 percent accurate. Given that Clare Short publicly vacillated between pro- and anti-war stances before coming down on the side of the government, it was hard not wonder why the interviewer didn’t press her on what made her change her mind.

Alongside political thinkers, government ministers and key activists, we also get to hear some celebrity testimony. Damon Albarn, Ken Loach, Richard Branson, John Le Carre, Brian Eno all line up to tell us how they got involved and how jolly angry they were. Branson tells of a scheme that he hatched with Nelson Mandela to get Saddam out of Iraq in a Virgin plane which would, apparently, have facilitated the restoration of a constitutional democracy to Iraq almost instantly. John Le Carre’s family all joined the demo, which was nice. Brian Eno seemed bemused that the UK  government seemed to have found different answers to the same questions he was asking and Damon Albarn offered his opinions on the movement. In fact, we got a lot of Albarn. He’s a prolific, innovative musician and a very nice man, but I’m not sure why I got to hear more from him than Noam Chomsky.

The film’s publicity relies heavily on celebrity appearances when it doesn’t need to. I’m grateful that Susan Sarandon and Danny Glover were part of the protest movement, but I was far more interested in the anti-war protests staged by US military veterans’ or the more eccentric actions: for example the nice American ladies that follow Dick Cheney and Donald Rumsfeld around posh dos, yelling “War Criminal!!! Arrest this man!!” until they get dragged away by security.

Where the film succeeds is in vindicating the protests: we were right to oppose the war because there were no weapons of mass destruction, Saddam Hussein was a brutal dictator but he wasn’t responsible for the September 11 bombings. The war happened in spite of mass global opposition because the US government wanted to finish off Saddam Hussein. The build up to the protests and the emotion of the actual day, are beautifully presented and the disappointment and horror at the actual invasion leaps off the screen.

And this is where the problems start. We’re left in a pit of despair, gasping in disbelief at the drone strikes, the crying children, the devastation and disillusionment. So the logical thing for the film to do is to provide that ray of hope that pulls us out of the pit. The ray of hope is that while the global demonstrations didn’t stop the war, they started a fire: democracy movements in Egypt were inspired to escalate their struggle (or irritated into indignant action, depending on who was being interviewed)  and the logical consequence of February 2003 was the Arab Spring that began in Tunisia in 2010. The protests also, we are told, were instrumental in giving the UK Parliament the courage to vote against invading Syria in 2013.

The problem with that argument is that it leaves out far too many things that happened between 2003 and 2010. The scandal surrounding the ‘dodgy dossier’ and the hounding of David Kelly, the first Ukrainian revolution, the global financial crisis, the replacement of party and ideology with single issue and identity politics, the muting of traditional vehicles of protest with techniques like kettling, the assassination of Osama Bin-Laden, the fall of Gaddafi, the rise of Daesh/ISIS, the wars in Southern Sudan… I’ll stop now.

It’s a bit much to ask a single film to cover everything that occurred in the past 12 years but We Are Many is so keen to push its thesis that it fails to acknowledge other contributing factors, or even look at what happened after the demo. For example, the Stop the War movement in the UK seems to end at the start of the war, though it struggled on with regular meetings and marches well into the next year. The rise and fall of Respect in the wake of the war doesn’t even get a mention, which is probably a blessing: nobody needs to see George Galloway in a leotard ever again.

So does the film succeed? I think it works in justifying our reasons for protesting at the time: we were right. The governments should have listened to us and worked for a peaceful solution that neutralised or deposed Saddam and restored a functioning liberal democracy to Iraq. That’s good to know and it’s good to have that confirmed so concisely and intelligently. However, the optimism with which it greets the vote on Syria as some miraculous restoration of our faith in Parliamentary democracy ignores the growing disillusionment of the British public with what it perceives as an elite political class that is increasingly out of touch. The gentleness with which the film treats some members of that class and the central thesis that weekend demonstrations have an influence beyond salving a few thousand consciences seems at odds with the wider picture. The spirit of non-violent protest is alive and well, but it lies beyond the Saturday demo.

Sarah Slade likes a nice demo and can be found holding the Non Aligned Lefty Cat Lovers banner near the back. Or you can troll her @sladey66.

We Are Many is on in selected cinemas tomorrow (with a satellite Q & A) and is out on Friday.