The British Red Cross is using its annual fundraising week, which ends on Saturday, to issue stark warnings on terrorism in the hope of attracting 10,000 civil protection volunteers.
The charity is distributing three million "tip cards", which contain hints on what to do in an emergency, and producing 20,000 copies of a one-off newspaper called The Uncertain Times on a similar theme.
The majority of cards, which contain 10 messages such as "keep your family and friends' home and work numbers with you", were distributed to readers of The Daily Telegraph and Radio Times.
It is the first time the Red Cross has included such awareness themes in its fundraising week. Chief executive Nicholas Young said: "We are living, unfortunately, in uncertain times. There is a very real threat of an attack in the UK."
A spokeswoman added: "After discussions, local authorities have asked us to meet the gaps in emergency planning."