Britain's Prime Minister David Cameron pledged to fight the "poisonous narrative" of extremists in his New Year's message.

"When our national security is taken on by a seething hatred of the west, one that turns people against their country and can even turn them into murderous extremists, I want us to be very clear - you will not defeat us," Cameron said in his televised address on New Year's day.

"And we will not just confront the violence and the terror, we will take on their underlying poisonous narrative of grievance and resentment. We will come down hard on those who create the conditions for that narrative to flourish and we will have greater confidence in, indeed we will revel in our way of life because if you walk our streets learn from our schools, benefit from our society, you sign up to our values - freedom, tolerance, responsibility, loyalty. These are the big challenges of our age, some of the biggest our nation has ever faced and this year is a test of our mettle," he added.

In November, Cameron said that Britain will increase its intelligence agency staff by 15 percent and more than double spending on aviation security to defend against Islamist militants plotting attacks from Syria.

The decision to bolster Britain's defenses came following a growing number of plots against the country and the attacks in Paris, Tunisia and elsewhere, Cameron explained.