Why the Home Guard was not an ordinary militia

What would the Home Guard have done to survivors of a failed Operation Sea Lion landing?

Its veteran-heavy manpower would have made it a formidable local force, not a collection of civilians receiving weapons without experienced leadership.

Many members were experienced First World War veterans in their forties and fifties. Civilian work in factories and agriculture also meant that a large share remained physically accustomed to demanding labor. Their military skills could be refreshed before introducing new tactics and equipment, unlike a force assembled entirely from untrained citizens. That accumulated experience made the Home Guard more dangerous to an invader than raw headcount suggests.