Site Records

Site Name: Chancery Lane deep shelter & Kingsway telephone exchange

31 - 33 High Holborn

Sub Brit visit 13th July 1996 & 25th February 2008

The description of Kingsway exchange as an underground town was not far off the mark, with its unique subterranean population and passageways such as ‘Third Avenue’, ‘By-Pass Alley’ and ‘The Dog's Leg’. Two parallel tunnels, each a quarter of a mile long and 16’ 6” wide, formed the heart of the exchange, housing much of the equipment. Altogether three miles of racking were installed, carrying 337 miles of switchboard cable, along with the 1.5 megawatt generators for standby power generation.

Kingsway exchange had other peculiarities too. Earlier it was stated that no subscribers were connected, but like most large exchanges it did have its own `service PBX' for official telephones around the racks. This had the possibly unique accolade of having not one but two dialling codes, LTK in the London system and also the national code OLTK (0585). The result was that you could reach its numbers by dialling either 01-LTK or OLTK.

Photo:The trunk test suite in South Street East in 1968
Copyright photo from BT archives

The strategic importance of the Kingsway trunk exchange declined after the introduction of subscriber trunk dialling (STD); before this, trunk calls had to be made through the operator, who dialled trunk calls using lengthy and somewhat idiosyncratic dialling codes that took them as necessary through the various trunk switching centres around the country.  The significant growth in the number of long distance calls necessitated many new trunk switching centres to handle the additional traffic. A new switching and transmission plan for a new `Transit' network was announced in 1960 and implemented in the late 1960s. This work coincided with the `Sector Plan' for London, which aimed to decentralise the switching of trunk calls in London and supplement the existing trunk switching centres. There were to be new technology `sector switching centres' in the key central sector and in seven locations in outer London serving the suburban areas. A number of writers have noted some significance in the names chosen for some of Kingsway's replacements, Bastion, Citadel, Fortress, Rampart and Tower but this is probably more bravado than indication of supreme strategic significance, since other replacements were named at the same time after eminent scientists (naturally these new exchanges were also connected to the deep level network).

Recreation room. Copyright photo from BT Archives

Whatever the case may be, Kingsway was becoming more obsolete with each successive phase of trunk modernisation and in 1979 it was announced that the exchange would close within a year, its functions being transferred to Cavendish exchange in Houndsditch. The conversion of the trunk network to digital was the final nail in the coffin and towards the end, only the Main Distribution Frame (MDF) was still in service, linking a few circuits between other sites.

The merit of Kingsway's secure central location ensured its survival for other purposes;

during the early 1980s it provided a home for BT's London area group that serviced closed circuit television. Another part of these tunnels was used for the Kingsway Computer Centre (KYCC) between 1986 and 1990. This housed a secure backup for Icarus, (International Circuit Allocation Record Update System) located in central London, whilst another computer dealt with radio paging. These functions came to an end in 1990, since when the sole use of Kingsway exchange has been for storage.

To the public at large none of this activity was common knowledge, however. By the 1980s Kingsway exchange was no longer mentioned or discussed by BT, regardless of previous exposes by Peter Laurie, Duncan Campbell and others and with good reason. For BT's staff had now been joined by government personnel. The latter established separate accommodation for themselves in the two easternmost of the four main tunnels in the southern sector, some time in the 1980s to judge by the fittings. This accords with BT gossip at the time of Kingsway’s “invasion by men with scrambled egg on their cuffs” as one staffer described it and with the removal from the Headquarters telephone directory of the accommodation group covering Kingsway. Whatever the secrecy concealed then is now laid bare because the facilities have since been fully decommissioned and are no longer confidential.

Subterranea Britannica made two visits to Kingsway during the 1990s and on the first foray (4th August 1995) the door to this restricted area had its own bell push and spy hole; the accommodation was declared rather pointedly as being out of bounds. It was also marked as such on the orientation plan that was handed out. On the next visit (13th July 1996), however, members had total freedom to look around what was left of the facility. The heart of the new accommodation appeared to be a briefing room, with seating facing a screen at one end and a projection booth at the back; sleeping accommodation was also provided. According to an article in New Statesman (25th July 1985) this was the back-up site for the war control bunker known as ‘Pindar’, the primary site lying below the Ministry of Defence headquarters building in Whitehall. It is likely that Kingsway acted as temporary home for Pindar during construction of the Whitehall site and it is stated that the Tooks Court entrance (and modern passenger lift) to the Kingsway complex was purely to provide discreet and direct access to this special accommodation.

Photo:The main distribution frame in August 1995
Photo by Nick Catford

When the Chancery Lane tube shelter was first built the surface sites required were requisitioned by the LPTB and subsequently transferred to the Ministry of Works, as at other shelter locations. Its subsequent takeover by the Post Office made the position more complex and the whole affair offers a fascinating illustration of the problems that occur when a facility is constructed under emergency powers. As an occupant of pre-existing facilities, the Post Office had initially no hindrance in establishing Kingsway exchange in the shelter tunnels at Chancery Lane.

This position altered radically, however, with the approaching expiry of the emergency powers under which the shelters had been built. The independent operational nature of the telephone exchange lent it a status rather different from the remaining deep shelters and whilst ownership of the latter was vested in the Ministry of Works by the Tube Shelters (London) Act, which vested ownership, Kingsway needed an act of its own, the Post Office Works Act of 1959, which vested ownership in the Post Office. The provisions of the act were set out in the Post Office Works

Trunk test desks. Copyright photo from BT Archives
bill, which was debated in the 1958/59 session of parliament. The preamble of the bill stated that in the exercise of emergency powers the London Passenger Transport Board had constructed certain underground works situated partly in the Metropolitan Borough of Holborn and partly in the City of London and that the Postmaster-General had entered into occupation of those works and in the exercise of emergency powers had extended them. The same bill stated that in the exercise of emergency powers the Postmaster-General had constructed works in the City of Birmingham (Anchor exchange). In both cases the works were described as "a system of tunnels together with shafts and other means of access thereto from the surface and ancillary works".

The Bill had its second reading by the Lords on 20th January 1959 and was committed to a Select Committee. Petitions were deposited by five organisations, complaining that no indication of the depth of the works was given (withheld for security reasons), that no compensation was offered for any damage that might be incurred, or for reduced property values and arguing that surface owners should have unrestricted rights to develop their land.

One further complication surrounds the property at 31/33 High Holborn, which is now one of the two points of entry to Kingsway exchange (the other is the goods lift in Furnival Street. London Transport has ownership of the ground floor and basement of this building which was then leased to the Post Office and later, British Telecom.

Photo:Tooks Court personnel entrance and ventialtion shafts. The was demolished in 2002 and the site redeveloped. A ventilation shaft was incorporated into the new building on the site.
Photo by Nick Catford

Following Sub Brit’s two visits in 1995 and 1996 and a visit by the Greater London Industrial Archaeology Society (GLIAS) in October 1995 the doors to Kingsway were once again closed. At the time of our visit there was still a small permanent staff but this was withdrawn shortly afterwards and all requests for access by interested groups were then turned down on health & safety grounds, even BT staff weren’t allowed in.

The Tooks court entrance which was contained within a large brick building with two prominent ventilation towers was sold for redevelopment to Tooks Court Ltd. for 2.1.million pounds on 16th October 2001. Once the building had been demolished the shaft was capped and following an archaeological excavation a new office block was built on the site. This is now home to the Government Actuary Department.

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Last updated 2nd October 2008
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