london britain pledge monday commitment security defense nordic baltic nations change brexit seek reassure state affect foreign minister boris johnson describe russian antagonism foreign office say johnson would host meet foreign minister eight countries include estonia sweden latvia monday discuss issue include russia nato defense co-operation britain eu exit increasingly complex world britain remain reassure presence friends especially face continue russian antagonism north europe baltic region say statement ahead meet cite deployment british troop estonia march reach around 800 personnel statement britain stand ally face outside aggression commitment nato britain want safe secure world leave european union continue defend promote common interest rise challenge face together say uk say defense commitment nordic baltic state wo n't waver brexit