There is a bit of background to all this in a book called the Russian Outlook by Lieutenant-General Sir Giffard Martel published in 1947:
Quote:
From their point of view they looked back on a very grim period as regards their relations with our country Without going into full details of this past record, we can see clearly enough the sort of unpleasant thoughts that remained uppermost in their minds. While the British Empire was expanding in the last century we had consistently opposed any expansion on their part. We had resisted Russian influence in Persia and Turkey. We had opposed the opening of a Russian warm-water port in the Persian Gulf. We intervened in their country and tried to re-establish the East front in Russia towards the end of the First World War. In doing so we brought chaos and internal strife to Russia. They were not asked to attend at Versailles..............
In July 1940, when the Germans were fully occupied in the West, she took the opportunity to march into the Baltic states, and thus regain former Russian provinces under the guise of protective custody. In a similar way, she entered Bessarabia in August, and completed the restoration of the major portion of her old western boundary.
On June 22nd, 1941, Germany broke her treaty with Russia and invaded her country. Whatever our views may be about the propriety of this Russian treaty with the Germans, the fact remains that it was strictly adhered to by the Russians. This was merely one more case added to the long list of treaties broken by Germany.