A month ago my boyfriend's English mother asked me – in all innocence – if I'd been to the "Tamil Tiger march" in Westminster. She was referring to one of the many protests organised by the tenacious and active British Tamil Forum, camped 24 hours a day at Westminster for over a month now.

Given the many – and widely photographed – Tamil Tiger flags at the protests, little wonder she mistook Tamils for Tigers. Born a Tamil in England at about the same time the Tigers were founded, I know that, sadly, if you have heard of Tamils at all, you have probably linked us in your mind to a group of rebel fighters who pioneered the art of suicide bombing and once assassinated the prime minister of India, Rajiv Gandhi. Separating the Tamils from the terrorists isn't just about correcting an alliterative slip or an image problem – it's at the core of the Sri Lankan conflict, and why the international community is dithering over one of the most appalling humanitarian situations of our time.

In Sri Lanka right now, around 100,000 civilians are trapped in a war zone, where they are being shelled every day by their government. A further 200,000 are in army-controlled internment camps without adequate food or water – and no sign of them being let out any time soon. They are all Tamil, like me and my family. That is about 10% of the entire Tamil population in Sri Lanka. To put it into perspective, it's about a quarter of the population of the entire Gaza strip.

There are two possible reasons why this is happening. First, that the Tamil Tigers are terrorists, and civilian deaths are unfortunate collateral damage in Sri Lanka's domestic war on terror. Or, second, that killing Tamil Tigers is a ruse for killing Tamils, and that the government is using the terrorist line to spin a sinister agenda.

While the international community grapples with Sri Lanka's insistence that it is the former, a depressing body of evidence points towards the sinister. There is the censorship – areas restricted to journalists including the "safe" zone where undercover reporters have to sneak out news of horrors. There is the witch-hunt for dissenters – Sri Lankan bloggers report that the government has now set up a hotline to report on those who question the war, and Unesco just awarded its World Press Freedom prize to Lasantha Wickrematunge, the latest Sri Lankan journalist to pay the ultimate price for free speech. And there is the state-sponsored terror – Desmond Tutu and Jimmy Carter argued last year that Sri Lanka should be struck off the UN human rights council for its abuses: internment, torture and abductions.

Last week the British foreign secretary, David Miliband, valiantly tried to get the UN to intervene to stop what it has called a "bloodbath" (you can witness his efforts in the face of creaking bureaucracy here). But in the meantime, the Sri Lankan regime is still getting our support – and because he and every other foreign minister caveats their calls with "the Tamil Tigers are so terrible" line, they add fuel to the Sri Lankan government's campaign – which then continues to drop bombs on hospitals and children.

Not all Tamils are supporters of the rebels – I'm certainly not. Despite all the flags, I know that many of us who are turning out in Parliament Square have a humanitarian agenda, not a pro-rebel one. But if we want the crisis to stop, we've got to realise that there's no use condemning the Tigers and trying to save Tamils, because in the eyes of the Sri Lankan government, we seem to be one and the same. The hope of the civilians facing mortal harm and starvation in Sri Lanka is that the world will not watch in silence while their lives are destroyed – and will not be fooled by the constant carping about the ills of the Tigers as a justification for throwing every last grain of humanity out of the window.