Last Friday 15 September commuters ran from a homemade bomb on a crowded train at Parson’s Green underground station in London. This is the fifth terrorist attack we have faced in the last six months and the fourth in London.

Three of the attacks involved vehicles mowing down pedestrians by lone terrorists but yesterday an IED bomb failed to detonate correctly and most commuters were spared. The explosion caused life-changing burns and a stampede to leave the underground but no deaths. We should be grateful.

Yesterday Prime Minister Theresa May upgraded the risk of a terror attack to critical suggesting another attack may be imminent. An 18 year-old man has been arrested and held at Dover and another man has been apprehended in London.

Mrs May was right to say we need to carry on as normal: if we overreact, the terrorists win. However, ignoring them also means resolutely avoiding the temptation to introduce more draconian anti-terror legislation.

Terrorists attack free people everywhere including Muslims coming out of a mosque most recently at Finsbury Park in June during Ramadan. On this occasion the attack was motivated by Islamaphobia and carried out by Darren Osborne, a white Welshman.

After the Finsbury Park incident Mrs May said: “There has been far too much tolerance of extremism in our country over many years, and that means extremism of any kind including Islamophobia…”

But if the Prime Minister wants to be the protector of our freedom and democracy as well as law and order, she must be careful.

In the same speech Mrs May said it was diversity that made London great: “This is an extraordinary city of extraordinary people, it is home to a multitude of communities that together make London one of the greatest cities on earth, diverse, welcoming, vibrant, compassionate, confident and determined never to give in to hate.” She must hold onto this conviction.

We live in a liberal democracy, not a surveillance society, and this is what we must protect: freedom from terrorists and freedom to live, work and travel around the United Kingdom safely.