The terror threats in the UK earlier this month affected many travelers, many of which had purchased travel insurance policies. Many of the policies even contain coverage for Acts of Terrorism in a city or country which you intend to visit.
Terrorist threats, however, are generally not covered
The following from Access America’s (now Allianz Travel Insurance) travel insurance plans:
9. A terrorist act committed by an organized terrorist group (recognized as such by the U.S. State Department) that results in property damage, Injury or loss of life. The incident must take place in a domestic or foreign city in which You are scheduled to arrive within 30 days following the incident and Your tour operator (if applicable) must not have offered a substitute itinerary. For foreign terrorism coverage only, coverage for travel to or through countries in which such a documented or reported incident has occurred during the 30 days prior to purchase of insurance is excluded. Losses resulting due to the issuance of travel advisories, bulletin or alerts; war or acts thereof; civil disorder, riot or unrest; bomb scares or threats of terrorist activity; or terrorist acts against any Common Carrier (e.g., airline or cruise line) are not covered. …
One way to avoid some issues is to purchase a “cancel for any reason” policy. At least those travelling a few days after the threats were able to cancel their trip and recover up to 75% of the trip cost.