Britain sent Sir John Moore with 10,000 troops, a force large enough to alter the balance in Finland. Gustav IV proposed that Moore seize Zealand before fighting the Russians, a sequence Moore judged impossible with the troops available. When the king tried to detain him in Stockholm, Moore escaped in disguise, rejoined the expedition, and returned to Britain. The troops could instead have reinforced the Finnish field army directly or replaced Swedish troops in southern Sweden so those men could move to Finland. Direct service in Finland would probably have stretched Moore's orders, but the objection was to undertaking both campaigns. The expedition arrived on 17 May, after Sveaborg had already fallen.
Notable Point ยท 58:22-1:02:32
Why Britain's 10,000 troops did not reinforce Finland
Britain sent Sir John Moore with 10,000 troops, but Swedish plans for an offensive against Zealand kept the force from serving in Finland.