The Threat to the U.K. - 2

More from the Telegraph, quoting a source in MI5:

"MI5's resources have been stretched to the limit for the past few years. There have been times when there was nothing left in the locker, when all of our assets were being used on one operation.

"At the same time, we have to contend with the very real threat being posed by the Russians. Russia is a country which is under suspicion of committing murder on British streets and it must be assumed that having done it once they will do it again."

The source said MI5 was so stretched that some recent counter-terrorist operations against Muslim extremists had used up its entire surveillance resources, meaning other areas of security and intelligence work had inevitably suffered.