Was George Orwell a terrorist? Or trade union legend Jack Jones? Both left their homes to travel to Spain to fight General Franco’s fascists. They didn’t just incite people to take up arms, they actually bore weapons and took pride in armed conflict. Or take Belarusian dissidents who call for the end of the regime of hated dictator Alexander Lukashenko. Are they terrorists? Or human rights activists who advocate for the overthrow of Robert Mugabe?

The Government’s own independent reviewer of terrorism legislation, David Anderson QC is worried. He thinks the Terrorism Act of 2000 is so broad it could criminalise, for instance, an anti-vaccination blog. In a damning report published earlier this week Anderson argued that the definition of terrorism needs to be much narrower, or mainstream political speech or investigative journalism could be classified as terrorism - one of the most serious criminal offences.

The detention of David Miranda at Heathrow Airport last year sent a signal from the intelligence agencies that journalists would be treated as terrorists if they crossed invisible lines. Miranda, the partner of Glenn Greenwald, was thought to be carrying leaked documents from whistleblower Edward Snowden. When the intelligence agencies called for him to be detained at Heathrow under the Terrorism Act, the police (rightly) refused. Discrediting journalists by slurring them as terrorists is the modus operandi of Vladimir Putin, it’s just not what democracies do. The intelligence agencies weren’t deterred and returned to the police with a new request. They stated:

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“Disclosure [of the Snowden files], or threat of disclosure, is designed to influence a government, and is made for the purpose of promoting a political or ideological cause. This therefore falls within the definition of terrorism and as such we request that the subject is examined under Schedule 7”

The threatened publication of words - yes words - may constitute an act of terrorism. The case went to the High Court, with help from campaigning organisations such as English PEN. The decision in the case (now infamous as the Miranda judgement) outlined that writing (whether a blog or a book), may amount to terrorism if it is “for the purpose of advancing a political, religious, racial or ideological cause”, “designed to influence the government” and “liable to endanger life or create a serious risk to health or safety.” Yes, terrorism includes risks to health and safety. You really couldn’t make it up.

David Anderson’s review found the cumulative effect of all the strands of our anti-terror legislation deeply problematic. It doesn’t just criminalise journalism, but editors and even you, the reader. Once published, the possession of an article that falls foul of this broadly worded law could land you in prison for up to 15 years. It’s safer carrying heroin on you than the written word. Helping prepare the article would carry a life sentence. If you encouraged the writing of a similar blog, you’d face a 7 year sentence.

As the reviewer points out, this is highly unlikely to happen. Yet, the chill on freedom of expression is enormous. If you face such sanctions (and journalists have) you begin to self-censor. Is hard-hitting journalism being spiked by cautious editors, frightened of both this legislation, and a climate after the Leveson Inquiry where politicians feel free to intervene in the workings of the free press?

None of this is to say terrorism isn’t a problem - the only religiously inspired terrorist attack in the whole of Europe in 2013 was the murder of Lee Rigby in Woolwich. While the less well reported murder of Mohammed Saleem in Birmingham in April last year, points to the ongoing concerns over the far-right. Yet criminalising ideas is bad way to fight our enemies.

There is another way. As Conor Gearty has highlighted, at the height of the Second World War, magistrates were busy throwing people in jail for “causing despondency” among the public. Often these people were pacifists who, however wrong, were merely exercising the right to free speech that our army was out defending. Like now, it led to a heated debate in Parliament. During the debate, Winston Churchill shot up and declared:

"We are fighting for freedom, civil liberties and the rule of law, these magistrates have over interpreted the laws we passed, we have to stop them."

We need political leaders brave enough to argue for free speech. The independent reviewer is right, the Terrorism Act is too broad and chills free speech. Writers, such as George Orwell, were not terrorists. Nor are journalists or David Miranda. We need to debate reform.

Mike Harris is Campaign Director of Don’t Spy On Us and an advisor to English PEN