The Development of Telecoms - London North Region

North area (second largest in size in the London Telephone Region) covers 246 square miles of North London, stretching from Hackney in the south to Harpenden in the north and includes the well known Welwyn Garden City and the City of St Albans, which celebrated its millenary in 1949.

Among its more important subscribers are the BBC Television Studios at Alexandra Palace and the De Havilland Aircraft Company at Hatfield.

North London is also famous for the BT Tower, previously known as the GPO Tower, Post Office Tower or the London Telecom Tower. It was completed in 1964 and overtook Millbank Tower, (119 metres, 390 feet) to become the tallest building in London standing at 177 metres (581 feet). It held this accolade until 1980 when the title was taken by the NatWest Tower, (183 metres, 600 feet). Today the tallest building in London is The Shard which stands at 309.6 metres, 1016 feet. 

The main purpose of the BT Tower was to support the microwave aerials used at the time to carry telecommunications traffic from London to the rest of the country, as part of the General Post Office Microwave Network.

Due to the number of tall buildings being planned in London, a new taller tower had to be erected to protect line of sight for radio links. The original tower, sited on the roof of a neighbouring building was used to provide a television link between London and Birmingham in the late 1940s. 

The BT Tower total construction cost was £2.5 million and was designed by architects Eric Bedford and G R Yeats. It's shape meant that it would not be affected by strong winds in order to protect the communications aerials attached to it. The first 16 floors were used to house technical equipment and power. Above these floors was a 35 meter expanse to attach the microwave aerials to and then there were six floors of suites, office space, kitchens, viewing galleries, a souvenir shop and the piece de resistance was a revolving restaurant, operated by Butlins, called The Top of the Tower. It made a complete revolution once every 23 minutes and offered diners spectacular panoramic views across London. 

Unfortunately the restaurant was closed to the public after a terrorist bomb was detonated in 1971 and then public access to the building was ceased in 1981. The BT Tower is now a grade II listed building and only occasionally used for corporate events and special events such as Children in Need. 

Despite the fact that microwave links have now been replaced by subterranean optical fibre links, the tower is still used as the site of a major UK communications hub. The second floor contains the TV Network Switching Centre which carries broadcasting traffic and relays signals between television broadcasters, production companies, advertisers, international satellite services and uplink companies.

There are 128,000 exchange lines in the area, connected to 37 exchanges, of which 29 are automatic. The total staff numbers approximately 3,200.