Overwhelming Force

The attack on London was a vicious attack by the Scrint was part of the diversionary attacks during the early parts of the Scrin invasion. The started when multiple scrin units were deployed and skirmished with GDI. Soon more major forces, including a drone ship, arrived. These went about wiping out the GDI bases in the area and detroying major landmarks, including big ben and the parliment building. It was because of this and other attacks that GDI immediatly saw the aliens as a threat and fought back, eventually leading to the Scrins defeat on Earth