Police and MI5 have carried out a counter-terrorism operation which has seen nine people arrested under the Terrorism Act in Birmingham.
Several homes and business have been raided in Birmingham
BBC Security Correspondent Gordon Corera told News 24 the raid followed a period of surveillance by the authorities, who suspected that a terror plot of some kind was being developed.
What kind of terror attack do the police believe may have been planned?
It is clear that officials weren't worried about a mass casualty attack - in other words, a bombing, the kind of thing we saw on 7/7 - but something far more targeted.
Now the suggestion is that it involved the kidnap of an individual, possibly a soldier.
It isn't clear yet who exactly that might be, but the concern was that some kind of action might be imminent or might be close at hand, and therefore the decision was taken to carry out these raids very early in the morning.
What implications does this have?
This is a worrying development if it is confirmed to be true, because that tactic of kidnapping is something we've seen with a great degree of violence and brutality in other countries like Iraq and Saudi Arabia.
The impact of kidnappings, obviously on the individual being kidnapped, can be extremely serious, even deadly.
It also has a huge propagandistic and a huge psychological impact because of the kind of fear it spreads, particularly if you saw some of the tactics used in Iraq - beheadings filmed and put on the internet.
The police are looking for evidence and we don't yet know what they've found or if they will find anything.
How long had surveillance been going on by the authorities?
A number of weeks, perhaps up to six months - definitely an intensive phase for several weeks leading up to this. It was carried out by the security service MI5, the West Midlands counter-terrorism team and West Midlands Police, acting jointly.
Clearly they had their eye on something, intelligence came into the system which caused alarm and that in turn led to action.
Operations of a similar nature have not necessarily led to police finding evidence, such as the raids in Forest Gate where nothing was found and no-one was charged.
So there is a lot of pressure on these occasions to see whether there is the substance to back up those concerns.