British security source cites intelligence about possibility of attack being planned . - The UK government is not aware that the US has any plans to carry out a terrorist strike in Britain, but it does have contingency plans for such an event. Second source : Increased security precautions in effect at transportation hubs . Security threat level hiked to `` severe '' for civil aviation , London transport .
British security source cites intelligence about possibility of attack being planned . A possible Mumbai-style attack in or near London is a concern , CNN learns . Second source : Increased security precautions in effect at transportation hubs . Security threat level hiked to `` severe '' for civil aviation , London transport .