This proposal was resisted by the Commander-in-Chief, Home Forces, Sir Walter Kirke, who favoured a mobile reserve to counter invasion, but shortly afterwards, he was replaced by Sir Edmund Ironside. Late in May 1940, the Chiefs of Staff Committee decided that vulnerable beaches needed to be fortified with pillboxes and anti-tank obstacles.
With the German invasion of Low Countries in May 1940 came the realisation that the United Kingdom was vulnerable to invasion. Main article: British anti-invasion preparations of the Second World War Winston Churchill helps to build a pillbox at Poole in July 1940.
