Background

In England and Wales the Home Office are responsible for the provision of Prison Service, Emergency Services (Police and Fire Brigade) and Home Defence. In Scotland this is the responsibility of the Scottish Office.

During the Cold War period the Home Office Directorate of Telecommunications ( D of T) provided radio communications for the Civil Defence and Emergency Services. In 1991 it changed its name to DTELS. The Civil Defence communications were dismantled after the UKWMO closed in November 1992 but the Emergency Service radio systems continued under this body.

DTELS moved from the public to private sector when it was sold to NTL Broadcast on 1st March 1994. Emergency Service communications was then sold to ARQIVA who maintained the analogue network. A phased changeover of Police analogue radio scheme to Airwave secure digital network took place between 2004 and 2006. This was followed by the Fire Brigade VHF analogue radio which completed their move to Airwave by the end of 2009. By 2011 all three 'Blue Light' services had completely transferred from analogue systems to the secure Airwave network.

The UK Police first introduced VHF radios in 1946. In 1963 a Home Office circular indicates the planned introduction of radio for Civil Defence too. At this time Civil Defence radio schemes included the Auxiliary Fire Service and the Civil Defence Corp as well as the UKWMO. Initially Fire Brigades shared their counties Police radio system but by the end of the 1970’s all had switched to their own dedicated system. A few Police and Fire authorities opted out of the Home Office D of T contracts and went their own way.

During the early 1970’s the use of radio technology increased within the Emergency Services. In addition to county wide VHF radios in vehicles the police introduced personal UHF radios (P Set) in most towns and cities. UHF personal radios were introduced in the Prison Service too. Fire Brigades used UHF personal radios on fire grounds and retained firemen had their home call bell and warning siren replaced by a single tone radio pagers The Royal Observer Corps (ROC) master posts were given VHF radios as a back up to the landline connection.

 

The Cold War Connection

If Britain had come under attack from nuclear weapons the Police and Fire radio schemes described in the following topics would have played a major part in communications. By using radio links for some if not all of their radio channels operation was independent of Post Office / British Telecom land lines. The UKWMO network primarily used land lines with radio links as standby. Where landlines were used they were private circuits which shared the same network hardware as the telephone system but operated separately from it.

 

Major Changes during the 1980’s

In the UK the VHF FM broadcast band had been restricted to 88-97MHz whereas in Europe it was 88-108MHz and most VHF stereo radios in use covered the complete band. The BBC occupied the majority of this restricted band. In the UK the remainder was allocated to mobile radio. In 1979 the World Administrative Radio Conference (WARC) passed a resolution requiring the United Kingdom to remove its mobile radio allocation from 97-108MHz, as this was a designated broadcast band in Europe. The change had to be implemented by December 31st, 1989. Once the existing UK users had been moved the band was opened up for commercial radio stations.

Part of the broadcast band, 97-103MHz was used by the Emergency Services, which meant that the ordinary members of the public could eavesdrop on the Police communications with their home FM Stereo radio. So this change would afford them some privacy.

The Home Office D of T was given access to new frequency bands and others extended. The new bands were 70.5-71.5MHz, 143-144MHz and 152-153MHz. The two UHF bands were extended downwards by a Megahertz to cover 450-453MHz and 464-467MHz. The 80-85MHz band was reduced to 80.0-81.5MHz and 83.5-84.0MHz. New bands in the microwave region were also allocated.

The change to Emergency Service radios caused by the 1979 WARC was phased in between 1987 and was completed 5 months early on July 31st, 1989. During this phased changeover the opportunity was taken to restructure UKWMO radio communications too. This was very timely as a review of UKWMO communications in 1981 had identified a number of areas for improvement.

 

Organisation and Callsign Plan

Regional Wireless Depots

The D of T was organised along the same regional boundaries as the Home Defence. Within each region was a wireless depot. The 1950’s term Wireless has been superseded in the modern language by Radio, but modern maps often show mobile radio hilltop sites at W.T. Station for Wireless Telegraph Station usually indicating there Military or Home Office past history. The Regional Wireless Depots and their outstations were responsible for the installation and maintenance of the emergency service radios in the region.

The radio schemes operated by the Home Office and Scottish Office were allocated four character call signs beginning with M2. Most police force and fire brigade radio operators dropped the M2 prefix under normal operations and used the last two letters as an abbreviation in radio operations. M2QK would be 'QueKay'. Others used the phonetics words for the last two letters M2YM was 'Yankee Mike'. Leicestershire Police was one exception who used the whole of their callsign and ended every transmission with 'emtunnul out', it took me a while to realise the first word was actually 'em-two-en-el' (M2NL)

In England the first letter of the abbreviated call sign for each County Police or Fire scheme signifies the Region. Whether by design or accident this regional identifier is often the first or last letter of the place name of the wireless depot. All Welsh counties start with a W, Scotland doesn’t quite fit this naming scheme. The engineers at the wireless depot had a call sign M2R and the regional identifier. For example in Region 9, M2RY for the counties using M2YA-M2YZ.

M2xx Callsign Allocations