British, Baltic navies conduct Baltic Sea exercises By (0) The British frigate HMS Lancaster leads ships from Britain, Estonia, Latvia and Lithuania this week in joint exercises in the Baltic Sea. Photo courtesy of Royal Navy March 12 (UPI) -- Warships from Britain, Lithuania, Estonia and Latvia, with Sweden's air force, joined forces for an exercise in the south Baltic Sea this week. It is the first major operation of the Joint Expeditionary Force, a Britain-led partnership of nine northern European countries -- Denmark, Finland, Estonia, Latvia, Lithuania, the Netherlands, Sweden, Norway, plus Britain -- organized in 2014 for special-purpose missions, including warfighting and humanitarian assistance purposes.