On the eve of the 10th anniversary of 9/11 attack, Cameron, in an interview to al-Jazeera, stated that he spent hours trying to contact Samantha who was on a business trip in New York.
Samantha, who was two months pregnant with their first son Ivan, was at the shop near the world Trade Center and witnessed the demolition of the unique building.
Cameron's anxiety raised when he failed to contact with his wife as mobile networks crashed in the immediate aftermath of the attacks.
The news channel quoted the British PM as stating, "Samantha was actually in New York that day, in Manhattan, and I'll never forget the hours of ringing her mobile over and over again and not being able to get through because the mobile phone system was down."
"I remember exactly where I was when I finally did get through and how pleased I was to hear her voice," added Cameron.