Democratic states rest on a slate of deals between the government and the governed. A crucial one will soon be up for renegotiation when the Government brings forth its new Investigatory Powers Bill, encompassing the level of intensive surveillance an open society should permit its authorities to deploy in defence of threats from other states, terrorists and serious organised crime. As an insider within the secret world put it, Parliament’s job is to “reset the dials”.The debate is conditioned by the threats themselves, the patchwork of existing legislation, growing technological capacity at the disposal both of the state and those who would threaten it, plus the revelations of Edward Snowden about the technical reach of the so-called “Five Eyes” of the Weste