Former defence secretary to give speech coverage of threats against terrorism . He will pose ' greatest challenge to our collective security ' for defence . Putin 's comments will be discussed as ' undermining ' international security . his Hammond is to make the comments at Royal United Services Institute .
Former defence secretary to give speech warning of threats against UK . He will describe 'greatest challenge to our collective security ' for decades . Putin 's actions will be discussed as 'undermining ' international security . Mr Hammond is to make the comments at Royal United Services Institute .