One wave was to land between Divis Mountain and Lough Neagh and capture the airfields. Another wave was to land near Lisburn and cut off the
road to Dublin.
The threat led to the formation of the Ulster Home Guard. 26,000 volunteered to join. Possible landing beaches were mined and closed off with posts and barbed wire. Machine gun emplacements were built in concrete bunkers. Many can still be seen at Tyrella, Portrush and Portstewart. The land border with the Republic of Ireland was patrolled to prevent German spies attempting to infiltrate the country.
The German plan was frustrated because they no longer had air superiority, after losing the Battle of Britain.
Later in the war the Home Guard manned the anti-aircraft guns at Holywood and Londonderry but never had cause to go into action.
The Ulster Home Guard was disbanded in December 1944.