Short answers, pulled from the story.
The Anglo-Soviet Agreement was a declaration signed on the 12th of July 1941 by the United Kingdom and the Soviet Union, pledging mutual assistance in the war against Nazi Germany and committing both nations not to conclude a separate peace with Germany. It was signed by Sir Stafford Cripps and Vyacheslav Molotov and did not require ratification.
The agreement was signed on the 12th of July 1941 by Sir Stafford Cripps, the British Ambassador to the Soviet Union, and Vyacheslav Molotov, the Soviet People's Commissar of Foreign Affairs.
Germany launched Operation Barbarossa on the 22nd of June 1941, attacking the Soviet Union along its entire border. The invasion ended Soviet neutrality and prompted three weeks of negotiations, culminating in the alliance signed on the 12th of July 1941.
The Arctic convoys from Britain to the Soviet Union began the month after the agreement was signed, and a joint Anglo-Soviet invasion of Iran followed, opening a southern supply route to the USSR. These actions were direct military consequences of the newly formalised alliance.
The two principles of the Anglo-Soviet Agreement, mutual assistance and renunciation of a separate peace, mirrored the first two resolutions of the Declaration of St James's Palace and fed directly into the Declaration by United Nations, which was signed in January 1942.
Yes. The agreement was broadened by the Anglo-Soviet Treaty of 1942, which extended the partnership to a political alliance planned to last twenty years.