london britain propose new post-brexit security treaty european union monday seek maintain intensify cooperation thwart ever-growing increasingly cross-border threats sixth policy paper set britain vision tie eu quit bloc march 2019 government say want keep benefit eu security cooperation argue party interest proposal come days blast pack commuter underground train injure 30 people west london britain fifth major attack year already deep level collaboration eu security matter interest find ways maintain brexit minister david davis say statement new security treaty eu would underpin share principles make sure partnership agility respond ever-changing threats face paper say entirely new form agreement security necessary satisfactory precedent security cooperation eu non-eu state rely exist model would diminish british eu defenses britain publish series future partnership policy paper try nudge talk eu forward stall divorce settlement especially so-called brexit bill security cooperation see government officials one strong arguments gain leverage complicate talk unravel 40 years union seek ram point home monday paper simultaneously stress britain importance eu security need continue cooperation respond future threats evolve interior minister amber rudd say britain one lead eu contributors range measure data evidence share extradition measure eu police agency europol recent events uk across europe show criminal terrorist threats face vary increasingly international long-standing collaboration european partner allow us jointly address threats keep citizens safe say prepare leave eu therefore vital agree new way ensure continue security law enforcement criminal justice cooperation rudd say document rule britain seek membership police agency europol body use european arrest warrant provide fast-track extradition focus however find way keep operational capabilities provide instrument nothing change say britain bid post-brexit security pact