03/11/2015 10:04 GMT | Updated 03/11/2016 05:12 GMT

Anti-Semitism and Abuse Is Not Acceptable - Not Online, Not Ever

Students and their unions have always challenged hate speech. We work day in, day out to challenge abuse and harassment and defend free speech. But the price for speaking up and fighting for change is often smear campaigns and ridicule. Now with the coming of age of social media this bullying is resulting in people shutting down their accounts and switching off from what should be healthy and essential debate. The consequences for free speech are worrying but the effects on mental health and self-esteem are startling.

Bullying and abuse online is unacceptable, but the fact that it is online is not the problem. In the last few days alone, my Twitter stream has been a stark reminder of the very real and horrific reality of anti-semitism that Jewish students face in Britain. Izzy Lenga, the education officer at Birmingham Guild of Students, has been subjected to abhorrent abuse and threats for daring to challenge anti-semitism on campus. I'm going to be frank; this is not about being 'offended' by 'views we don't like'. This is people putting up a poster saying "Hitler was right" on Izzy's campus and people tweeting her to say that Jewish people should be "popped back in the oven".

There are the graphics that are constantly shared which call Jews "Zionist racist scum" and suggests the Holocaust was 'invented'. The people who write blogs that 9/11 was an "insurance scam" by "a secret Jewish network". Those who write on Facebook that "Adolf and Co should have finished the job properly", pose questions like "why stop at 6 million?" and the artists who depict Jews as thieves with big noses. This is anti-semitism. It is wholly unacceptable and it should not go unchallenged just because it happens to be online. Not when there has been a 50% increase in anti-semitic attacks in the UK since last year; not ever. My union will always be resolute in our defence of Jewish students in the face of anti-semitism. Now, when some 20% of this abuse is online we have a duty to do more to challenge it in all its forms. We are all incredibly proud of Izzy for standing up to this abuse, but nobody should ever have to deal with it.

This harassment is deplorable. But just because it is more public, it should not be a shock to us that social media contains constant streams of anti-semitism. The pernicious rumours, smears and abuse that Jewish students face is in society, just as much as it is on the web. Sexist abuse and misogynistic advertising is seen on public transport, just as it is on your sidebar. My own national officers at NUS have received streams of abuse, not just for speaking up, but for being women or being black. Just last week, Toke Dahler from Leeds University Union faced xenophobic posts for just appearing on Newsnight. This online, much more public, shaming, threatening and horrific abuse is now considered a norm within the daily routine of social media posts and messages.

I often ask myself whether it is worth the bother to open up my own inbox or switch on my phone knowing that it will be full of abuse. Simply making a decision in my job means I get called a 'bitch' - something that women leaders across the UK, and in fact across the world, will know all about. This is not people who are just trolling for fun, it is people who want to try and bully you to change your mind or marginalise you just because of who you are. They don't want you to have an opinion - let alone power.

NUS and students' unions have often been criticised for being 'offended' too easily and for shutting down free speech. But when we say that hate speakers who incite violence are not welcome we are ensuring that people like Izzy and that people like Toke can have a voice in the one place on campus that is free from intimidation and abuse - students' unions.

On my watch this union will continue to defend free speech by challenging and ending this vile hate speech. It is time that we all stepped up and played our part in facing down this disgusting abuse - whether online or on the street, once and for all.

Megan Dunn is the national president of the National Union of Students