Imagine the one you loved most has been killed by a fanatic bomb.

Imagine that the politicians' promises of turn to ashes; that the police investigation stalls.

That the bombers still walk free - and they will strike again.

Then hopes for justice turn to dark visions of revenge - especially as the identities of the terrorists are known to all - even 'the dogs in the streets'.

The relatives of the slain take the law into their own hands. For they carry their own guilt.

Maddy because, unwittingly, she sent her two small children and her husband out to meet their deaths. Rob because he had brought a little boy who had saved his life to Britain - only for him to be wantonly murdered.

Maddy and Rob - and the others - owe. And they will be avenged.