40 years ago today the first mobile phone call was made in New York. David Gilbert charts its humble beginnings and rapid development.
On 3 April 1973 Dr Martin Cooper stood outside the front doors of the Hilton Hotel in Manhattan. He was nervous. In his hand he held the world's first handheld mobile phone. No one had ever made a call from such a device before and he was about to do it in front of the world.
He switched on the Motorola DynaTAC, known variously as the "boot" and the "brick". Once it was powered up the phone connected with the cellular base station he and his boss at Motorola Dr. John F. Mitchell had set up especially on the Burlington Consolidated Tower, which then patched the call into the landline phone network.
Those in attendance watched on as Cooper pushed the buttons on the DynaTAC's face which showed up on its tiny LED display - before holding the phone to his ear.
So who was about to receive the honour of being the first person called on a handheld mobile phone? The President? His boss at Motorola? His mother?
No, Cooper was calling his arch rival, Dr Joel S. Engel of Bell Labs. Bell Labs was at the time a section of AT&T which was Motorola's prime competitor during the 1960s and 1970s.
Bell Labs had taken the decision to focus on car-phones rather than handheld devices, allowing Motorola to be the first to produce a true handheld mobile phone.
While the phone may seem unwieldy and bulky compared to the smartphones we use today, at the time it was revolutionary, because mobile telephones were bulky affairs installed in vehicles, or in heavy briefcases.
The DynaTAC (which stands for Dynamic Adaptive Total Area Coverage apparently) weighed 1.15kg and measured 9in x 5in x 1.75in. It promised 30 minutes talk time and took a whopping 10 hours to re-charge. It could store up to 30 telephone numbers.
It would be a whole decade later in 1983 when the DynaTAC went on sale in the US, costing almost $4,000.
The phone gained iconic status having being used in films such as Wall Street and American Psycho and more recently it was used in the videogame Grand Theft Auto: Vice City.
Unfortunately, for those holding onto a DynaTAC it is all but obsolete now as the AMPS network it operated on has been all but switched off.
To say that the mobile phone has changed in the last 40 years would be a huge understatement, with today's smartphones more powerful than some laptops and allowing you instant access to all of the world's information in the palm of your hand.
While Cooper might have been the person given the prestigious job of making the first call on a handheld mobile phone, it was his boss at Motorola Mitchell who did the most to push his company to develop wireless communication products that would be small enough to use anywhere and participated in the design of the cellular phone.
In order to use phones while away from a physical connection, the development of cellular networks was necessary and the first such system, commonly known as 1G, was Advanced Mobile Phone System (AMPS) which was initially rolled out in North America in 1978.
Having served its purpose, the 1G network was such down by most North American networks as late as 2008.
The system was superseded by 2G in the 1990s with the European-backed GSM standard battling with the US-backed CDMA standard.
During this time we began to see the move away from the brick-style phones towards the lightweight 100g smartphones we see today. Improvement in battery technology as well as the shrinking of processors and the development of flash memory all aided in slimming down the mobile phone.
As mobile phone ownership became the norm rather than the exception at the turn of the century - in developed countries at least - the functionality of these devices also increased.
Allowing access to the internet while on the move was the beginning of a much bigger revolution in mobile technology which would eventually lead to the smartphone explosion, but initially led to the development of 3G networks.
It was Finnish manufacturer Nokia who made the most of the huge popularity of mobile phones, taking the position as world's largest phone manufacturer in 1998, a position it did not relinquish for 14 years, when it was taken over by Samsung in 2012.
In 2007 the launch of the iPhone marked the next milestone in the evolution of the handheld mobile phone and sparked a smartphone revolution with the mobile phone industry now recording annual revenues of $800bn.
Mike Short, an expert from the Institution of Engineering and Technology, says the last 40 years of mobile phone evolution can be broken down into four distinct eras:
"Since its first use 40 years ago, the mobile phone has completely changed our lives. The first decade was a research or a 'demonstrator' phase, rapidly followed by analogue networks deployed over 10 years from the early 1980s largely based on carphones and used in business in the developed world.
"This soon led to the digital decade mainly between 1993 and 2003 when consumerisation and globalisation of mobile really took off.
"This led to a further data adoption phase with the arrival of 3G and during 2003 to 2013 access to the internet and the wider use of smartphones became a reality."
With the advent of 4G, we are now arguably entering the fifth era of the mobile phone age, where unrestricted access to everything the world has to offer is available in the palm of our hand.