When I went last year, leaving from Luton , I flew with El Al, the customs guys took me aside before flying and interviewed me for over an hour.
Also took swabs of all my belongings and clothes. It was a right pain in the arse.
All because I had a lap top with me that had been in for repair about a month earlier and so I couldn't account for its whereabouts for about 2/3 days.
Surprising really as I have such an angelic face.