The first in a new ten-part series of the political programme.
American presidential candidate Barry Goldwater said "Extremism in defence of liberty is no vice." But how far should we in Britain go to protect ourselves after the terrorist attacks on the US? With greater police powers and the introduction of identity cards on the agenda, David Walker asks whether there is always a trade-off between security and freedom, and where the balance should be struck.
(Repeated Sunday 9.30pm)