Hack Green started as a radar station in World War II.
After the war it sat empty for a few years until it became part of the 'ROTOR' project in the late 1940's to help with the early warning system of enemy bombers armed with nuclear weapons. It was equipped with radar and a two-level R6 bunker. The site developed into a major air traffic control station - civil and military - known as Mersey Radar. It operated continuously until the mid 1960s.
In the late 1970s, the Home Office took over the site and it became RGHQ ( Regional Government Head Quarters ) 10.2 in about 1985. Every trace of the radar site was removed, except the reinforced concrete box that formed the the Rotor bunker. A new two-level semi-sunk bunker was built in it. A mezzanine floor divides up part of the lower floor, giving three levels in part of the bunker. In total there is about 30,000 ft2 of floor space.
The bunker, like most of the RGHQs, was sold in the early 1990s. It is in excellent condition and a great example of the larger nuclear bunkers.