Defence and Security Review (NATO)

The hon. Gentleman referred to Estonia. Clearly, under article 5 of the NATO treaty all the other 27 member states would have an obligation to respond to an armed attack on Estonia, but there is a level of ambiguity, given the hybrid warfare that the Russians are engaged in and have been engaged in—cyber-attacks and others. Given that Putin does not necessarily wish to invoke a major military conflict, how does NATO deal with those hybrid attacks?