What is insane is not really his specific case, but the last paragraph of the article about the law in UK:

   Under Schedule 7 of the Terrorism Act, police are allowed to stop anyone passing through a UK port “to determine whether they may be involved or concerned in the commission, preparation or instigation of acts of terrorism”.

   The person who is detained can be held for up to six hours, is legally obliged to answer questions and must provide the password or access number for electronic devices, or be held to have committed a criminal offence if they refuse.

So, basically, just because you pass the border, English citizen or not, you have to provide the password to all your devices on request, without even a probable cause or any justice decision or oversight. And if you don't comply, you will be sentenced as a terrorist...