Site Name: Longley Lane Rotor Sector Operations Centre 'LOA' & Filter Block later Preston AFHQLangley Lane & Whittingham Lane
RSG site visit 7th June 2000
[Source: Nick Catford]
Each of these four complexes consisted of no less than three bunkers, typically a few hundred yards apart. One was the operations room, another was the filter room, and the third was a communications centre. During the war the complex acted as 9 Group Operations Centre Fighter Command.
After the war the operations room was adapted as one of 6 Sector Operations Centres as part of the Rotor Radar Project with the code name LOA. Longley Lane and Box SOC's were the first to become operational in 1950.
Photo: The Longley Lane operations room after conversion to ROC Group Control
Photo by Nick Catford
There has always been some confusion over the name this probably dates from a change of name in 1950 when under the Fighter Command Outline Plan (AIR2/11178) RAF Barnton Hall was re-named RAF Longley Lane. It seems likely that it was a typing error at that time but the incorrect name was retained.
The SOC's were designed to exercise the intermediate control and reporting functions under Fighter Command HQ, Bentley Priory. The UK was divided into 6 sectors, each with an SOC. Fighter Command HQ and the SOC's received raw data from radar stations and ROC Group HQ's; after filtering to remove anomalies this data was retold to the SOC's who were responsible for the actual control and interception via GCI stations. Army AAOR's also received the same information to integrate defences.
With the introduction of the Type 80 radar in 1953 it was apparent that the control and reporting functions could be provided at the same installation and with the delay in data transfer to the SOC's and back it was found quicker to control the interceptions from the GCI sites.
With the advent of the H bomb in 1955 together with modern bombers, the rotor system as it stood was superseded by technology and events and the network of Master Radar Stations (MRS) was introduced. Several rotor sites became Master Radar Stations but the SOC's and the AAOR's became redundant. Longley Lane was one of the first SOC's to close, probably in 1956. In 1962 the bunker was adapted as ROC Group Control for 21 Group at Preston (see Langley Lane)
During the war the filter room acted as a collecting point for information. Duplicate and irrelevant information could be filtered out here. It was later used for many years as the Preston Armed Forces Headquarters (AFHQ) . The two level bunker had been empty since 1992, its last use being as a military firing range. It was offered for sale by tender by the Ministry of Defence in June 2000. Prior to the sale there were two public open days for potential buyers. The bunker no longer had any power and was flooded beneath the floorboards in the lower level and in the lower plant room. Before the public could be allowed in temporary lighting had to be installed and most of the water was pumped out.
The bunker is located on the south side of Whittingham Lane in 0.74 acres of land and is securely fenced. (SD54953625) All that is visible from the road is a grass covered roughly rectangular mound approximately 15 feet high with two air vents on the top. There are two entrances into the mound fronting onto the road. Between the bunker and the road there is an underground oil storage tank and an electricity sub station.
Photo: The filter block in Whittingham Lane
Photo by Nick Catford
We entered by the main entrance into a short corridor leading to the main east - west corridor. A few yards inside the main entrance steps lead up to the generator room. The generator is intact and appears to be in good condition although vandals got into the site some time ago and have damaged the control panel, pulling much of the wiring out. As we entered the main corridor turning right led immediately to a flight of stairs down to the lower level. We turned left and the first door on the right led onto the balcony which goes right round the central well of the operations room with narrow wooden steps down one side. The next three rooms on the right were all empty and we were told they had been dormitories. After the third room we reached a 'T' junction, left led out to the emergency exit. We turned right and on our left there was a small store room, a larger empty room, male toilets, another stairway down to the lower level and another male toilet. We then turned right again past three more dormitories that were all empty and through a door onto the balcony.
Photo: The Filter Block Control Room
Photo by Nick Catford
Going down the stairs inside the main entrance to the lower level we came to another short flight of stairs down below the level of the operations room. It was damp down here and the tide mark on the wall showed that the water had been at least two feet high. There were some electrical boxes on the wall and a door into a large ventilation plant room. All the ventilation plant was intact but as part of the control cabinet has been under water for some time it is probably now useless. We retraced our steps up the short flight of stairs and along the lower corridor where the main door on the right led into the main operations room which has always remained just above the water level and its wooden floor is still in good condition. We lifted a trap door in the floor and could see the water a short distance below.
The only evidence of past use are to be found here in the form of two 8 foot high vertical movement wall boards manufactured in West Germany by Weyel. One board was a front illuminated map of the north west coast area running inland from North Wales in the south to just south of the Scottish Border in the north. The board next to it had details of troop movements on it. Returning to the main lower corridor the next room on the right was the canteen, completely stripped out with a serving hatch into the kitchen. The kitchen consists of two large rooms and a smaller room which had been a larder. Most of the kitchen equipment, cooker, sinks, work tables etc. were still intact. Turning right at the end of the main corridor there was a female rest room and toilet on the left followed by stairs up to the upper level then another male toilet. The corridor then turned to the right, past two more dormitories on the right and through a door into the operations room.
Documents in the PRO (namely the Operational Record Book (ORB) or 'Form 540', located together in the same class with other ROTOR period ORB's) show that the Longley Lane site (the WWII operations room) was used as a Sector Operations Centre (SOC) in the ROTOR air defence system, other authorities claim that documents may indicate that minor works were completed but the site was never equipped. 
The communications site is now derelict and a local farmer uses it as a vehicle store.
[Source: Nick Catford
Last updated 7th September 2003
© 2003 Subterranea Britannica