"The threat is huge. It dipped slightly and is now rising again within the context of 'severe'.
"There are large complex plots. We unravelled one, which caused damage to al-Qaeda and the plots faded slightly.
"However, another great plot is building up again, which we are monitoring.
"We have done a great deal to protect ourselves and to look after our water supplies, our resilience, underground trains, our preparedness and communications.
"We have done all the things that we need to do, but the threat is building - the complex plots are building."