The former Ukip leader hit out at Amber Rudd and the Government over what he suggested was a failure to tackle the problem in schools and prisons.
Appearing on Sophy Ridge on Sunday, the MEP said the fact Westminster killer Khalid Masood was born in Kent was a problem that needed to be addressed.
Mr Farage added a clear immigration policy was necessary and Britain should not “add” to its “home-made problem”.
He said: “This is worse. This is even worse. The fact that people are being radicalised inside our prisons and we appear over the last few years to have done nothing about it. So we’ve got two problems. But given we already have a problem with people being radicalised at home, why on earth would you want to add to it with an irresponsible immigration policy.
Nigel Farage said there was a home-grown terrorist problem that needed to be addressed
As we have a home-made problem already, let’s never add to it
With Ridge suggesting he was making a different point, Nigel Farage responded: “I think your researchers have made a slight mistake. I was very specific when I talked about Jihadism across the whole of Europe and I repeat the point, as we have a home-made problem already, let’s never add to it.
“The point is there are lots of terror attacks taking place all across Europe and many of them are people who literally just arrived. Now that’s a bigger problem for France and Belgium than it is for us because we’re not part of the Schengen zone thank goodness. We’re leaving the European Union, even better, but we still have to be on our guard.”
Meanwhile, a study of CCTV camera footage from Wednesday’s terror attack and the timing of 999 calls revealed it took just 82 seconds for terrorist Masood to murder four innocent people and injure 50 more.
London terror attack: Latest pictures Fri, March 24, 2017
4 dead and 40 injured in London terror attack
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Armoured police personnel carriers are seen on a street leading to the Houses of Parliament in central London on March 24, 2017 two days after the March 22 terror attack on the British parliament and Westminster Bridge
It shows barely a minute-and-a-half passed from the moment his rented vehicle mounted the pavement on Westminster Bridge to the moment he was shot by a police firearms officer.
Detectives from the Metropolitan Police’s Counter Terrorism Command confirmed on Saturday night that Masood swerved his car on to the northbound pavement at 2.40pm and eight seconds on Wednesday.
The rampage, in which he used his Hyundai Tucson 4×4 SUV to plough into pedestrians, lasted just 30 seconds before he crashed the car into the perimeter fence of the Palace of Westminster.