Ex-security minister Baroness Neville-Jones has criticised the culture of smartphone use, saying she is "alarmed" by the number of people unaware of their surroundings due to technological distractions.
Speaking to BBC Radio 4's Today programme, Lady Neville-Jones said: "I think being alert is very important. I am alarmed by the number of people I see wandering along the street entirely engaged in their mobile telephones and with their ears plugged into music and they are not aware of their surroundings. You need to be aware of your surroundings.
"You do have to take some personal responsibility. I do think we can be more alert than we are."
Lady Neville-Jones, former head of the Joint Intelligence Committee, suggested members of the public should ditch their devices in order to gain more awareness of their surroundings while the terror threat level is high.
Official guidance is for people to be "alert but not alarmed" at the threat from terrorism, PA reports.
"I do think we are going to have to get used to what we have seen yesterday in Germany - that is to say alerts which close places of public functions, and higher levels of security in big public gatherings," the Baroness added. "That is prudence and proper caution on the part of intelligence and the police authorities."
She said the authorities had to take any intelligence seriously: "If you have got a piece of information, it may be difficult for you to assess it, you may not be comfortable about having a broader picture - part of the problem with intelligence is it can be fragmentary - but it's a very bold government or policeman who chooses not to take precautions in such circumstances.
"I think the population on the whole would prefer them to be cautious and occasionally have closed something that it turned out wasn't necessary, but how do we know, rather than take the risk of exposing people to dangers on which they have information, even if it's not complete and on which they can't necessarily totally rely."
You can listen to Lady Neville-Jones' full interview on BBC Radio 4's Today programme here.