NATO Secretary General Jens Stoltenberg met Prime Minister Theresa May.
AWACS were deployed to guard the airspace over an EU summit.
Forces from across NATO are currently taking part.
The crisis management exercise CMX 2019 will take place this month.
Raytheon has won a contract to support large-scale, live training exercises.
Supreme Allied Commander Europe (SACEUR) General Curtis M. Scaparrotti hosted a commander's conference.
Experts from NATO and Ukraine took stock of progress made on several projects.
NATO’s Aegis Ashore Ballistic Missile Defence site will undergo a long-planned update this summer.
A response to a written question has revealed the extent of British support for the defence of Ukraine.
Later this week German, Polish and Swedish fighter aircraft will practice Quick Reaction Alert procedures over Estonia.