UKIP Home Affairs spokeswoman Jane Collins MEP has said today's terrorist attack on Westminster is "an attack on the very way of life in the UK."
The man pictured being surrounded by police in the grounds of the Palace of Westminster was of South Asian origin and bearded in the traditional Muslim style, although his identity has not been confirmed.
"We need to take the seriousness of radical Islam seriously: this is a problem here in the UK which today has cost the lives of four people and catastrophic injuries to others.
"Police are treating this as a terrorist incident with an investigation ongoing and it shows the hallmarks of being an attack by an Islamic terrorist. Groups such as Islamic State have welcomed the news, saying it is revenge for the fight in Mosul where our Armed Forces are helping liberate a city living in misery and terror.
"I want to take nothing away from the brave men and women of the emergency services, the Armed Forces and the Security Services, including tragically one who lost his life in the line of duty.
"But demonstrably we are living with a daily threat to our way of life. Innocent people were mown down walking across a bridge and Westminster was targeted because it is the symbol of our democracy.
"We must never give in to terrorism but that does not just mean we have to dust ourselves down after an attack, it means we have to root out the cancer of radical Islam, stop allowing radical preachers to spread their hate even if it means monitoring mosques because it was at Finsbury Park this man was radicalised, and stop being afraid of naming what we are dealing with for fear of being politically incorrect."