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Mobile phone celebrates 40th anniversary

3 April 2013 Last updated at 14:23 BST

The first mobile phone call was made 40 years ago today, on 3 April 1973.

Martin Cooper, a senior engineer at Motorola, called a rival colleague at another telecoms company and announced he was speaking from "a 'real' cellular telephone".

In 2012 a report carried out by the International Telecommunication Union found that there were six billion mobile phone subscriptions worldwide.

Simon Gompertz reports.