Bernard Kerik, the former New York City police
commissioner, joins the show

As the United States begins the summer holiday season repeated announcements of 'heightened terror alerts', the confusing 'national threat' colour coding system and the continual warnings to 'be on the lookout for suspicious activity' are enough to strike fear into the calmest of hearts. 

But how real are the threats and do all these warnings create an unwarranted climate of fear?

Nearly six years after September 11, security officials believe that it is only a heightened sense of vigilance which has kept America safe from terror. 

However critics of the terror alert system argue it is being used to justify an erosion of civil liberties at home and an expansion of military action abroad.

On Tuesday's Riz Khan we talk to Bernard Kerik, the former New York City police commissioner, who argues that the threat of terrorism in the US is very real. 

He believes the public should take serious heed of the warnings coming from Homeland Security and other government offices, especially in the light of the recently thwarted terrorist attacks in the UK.

Also joining the programme is trauma psychologist Dr. Robert Butterworth who will discuss the 'climate of fear' and its impact on the nation's psyche. We ask how real are these threats, where are they coming from and what you should do about them.

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This episode of Riz Khan aired on Tuesday 17 July 2007.

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