But whether it is military explosive, whether it is commercial explosive, whether it is plastic explosive, we do not want to say at this stage,

All three bombs on the London Underground system actually exploded within seconds of each other, at 8:50 in the morning,

There is a possibility that the person with the bomb died on the bus, there is a possibility they left the bomb, ... We're not ruling anything out, we're not ruling anything in.

We have to be aware of unintended consequences of legislation in terms of whether it affects people's willingness to come forward.

A slightly different picture is emerging around the timing of these bomb incidents,

We are making an urgent appeal for any photos or videos -- including from mobile phones -- taken Thursday morning close to where the bombs exploded.