All the basic technologies for mobile phones were in place from the late 1940s: wireless, telephony, cellular network design and frequency re-use. All that it required was the software and hardware to make it work.
But it was to prove difficult to come up with something that would work - and something that people would want to use.
Japan was easily first to introduce a commercial cellular telephone service operating in Tokyo in 1979.
It wasn't until 1983 - nearly four years later - that Ameritech opened a similar service in Chicago, using Bell's Advanced Mobile Phone System (AMPS).
It would be a further two years before cellular mobile phones reached the UK. It is a far cry from today's innovative mobile market, with the top brand names offering a range of different functions to entice the ever eager consumer. Sending photographs to your friends and family, and downloading music may seem cutting edge - but network operators still have lots of ideas up their sleeves to keep the mobile phone at the forefront for interaction and entertainment.
When you switch on your mobile today you assume there will be a service in most places. Indoors or outdoors, in the city and in much of the country, you take coverage for granted.
But it was not always like that. When Cellnet opened for business in 1985 there was just one transmitter or base station, sited on top of the BT Tower in London, covering the whole Greater London area.
Vodafone had more cells - but not many. Development was rapid and soon all major cities were covered, along with the motorways connecting them. Additional base stations then filled in the gaps.
The government imposed a 90% coverage requirement on the operators that was soon met. Today, leading cellular network operators claim coverage rates of close on 99% of the UK population (calculated for populated areas, not the entire land mass). And with the advances in technology 'roaming' devices allows us to use our mobile phone to speak across some 650 networks to people in more than 200 countries.
Before reaching the micro-technology of today's mobile phones, cell phone users had to go through a period of arm-stretching portability, which seemed closer to carrying a brick than a state-of-art telephone.
Early cell phones were heavy. They had to use large components and the batteries were huge by today's standards. Cell phones in cars were more practical because they had access to a large battery, but for people who had to be in contact on foot there were two other options.
The batteries on hand portable phones allowed 10 x 3 minutes of talktime, which meant that for the serious conversationalist this transportable cell phone was a better answer. Perhaps luggable is a better description than portable. Either way this phone helped start the trend that has led to today's multibillion pound mobile phone business.
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Today's mobile users would not enjoy using those first handheld units from the mid 1980s. These came in three varieties - 'hand portable', 'transportable' and 'car-phone'.
The 'hand portable' was far from handy and hardly pocket sized - unless the pocket was huge. And the 'transportable' was like a shoebox filled with concrete.
The technology was primitive - with transistors that were greedy on battery power, large-scale integrated circuits not originally designed for mobile phones and huge alkaline batteries.
Nevertheless, they all worked well enough to suit the so-called 'early adopters' - and as user numbers grew, manufacturers poured huge research and development efforts into producing cheaper, handier equipment.
So much so that over 15 years they have transformed an unwieldy executive status symbol into a truly lightweight, pocketable, affordable and indispensable tool of modern life.
