The larger effect of the entire sequence of events was to drive Denmark and Sweden somewhat closer diplomatically to Germany. They maintained their minefields and nets (with German assistance) until the end of the war. While the Danes did occasionally “turn a blind eye” to surface warships transitting the Grosser Belt minefields, both nations permitted no submarines of any nationality through the minefields. In addition almost every ship after November 1915 was thoroughly checked before it passed through their fields. Sweden and Denmark did maintain commercial ties with Britain. In particular, the Swedes exported a great deal of timber products to Britain as well as some iron ore concentrate, but most of it was shipped through Narvik, Norway. At the same time both nations became even more involved in commerce with Germany. Danish fish exports to Germany doubled after this incident.
The British were unable to get any more submarines into the Baltic. The three-boat Baltic Flotilla turned out to be a bit of a bust. It had to be supplied (particularly torpedoes) through Archangel and bottlenecks there kept the flotilla tied to the pier for much of the war. Later, the flotilla moved to Helsinki due to approach of German armies. At the same time, logistical problems became more dire. As time went on first Goodhart’s E8 and then Halahan’s E18 were cannibalized for parts and ammunition to keep Cromie’s E19 on patrol. Cromie was by far the most successful of the Baltic Flotilla skippers, sinking four more ore carriers. Halahan got two more and Goodhart never even made contact. Ice impeded operations beginning in November and the subs spent a lot of time immobilized by the ice.
Captain Blake got his crews out through Archangel as Russia left the war, with one exception. Commander Cromie was murdered by a Russian national as Russia disengaged. The subs were scuttled to keep them from falling into potentially unfriendly hands.
Commander Laurence and the balance of the crew of E1 remained in their sub-Arctic internment for the remainder of the war. Laurence and Tilda Louise exchanged a couple of letters, but just before the end of the war, an epidemic (initially thought to be typhus) in Landskrona and took the life of Tilda Louise as well as those of the Doktor and the constable who had rescued the crew of the E1.
Lieutenant Paul Eddis never went to sea again in a submarine. He finished his RN career in the early 1920s as a Lieutenant on a battlecruiser.
Geoffrey Layton went on to a long and eventful career in the Royal Navy. After a short hiatus, he commanded another submarine in an uneventful period, and after the war was active in the development of Royal Navy submarines, becoming the Chief of Submarines. Layton eventually rose to the rank of full Admiral and commanded Royal Navy assets in the Far East. He retired in the late 1940s.
Neither the Royal Navy nor Whitehall ever had a record of anyone named Harvey Anderson on their payroll during this time. Both services denied any knowledge of any of their personnel being involved in the escape of Geoffrey Layton from internment.
There was, however, a Professor Harald Anders who taught Scandanavian languages at Cambridge noted in the early 1920s.