Quarter of world online as internet turns 40

In October 1969, teams at Stanford Research Institute and UCLA began tests to send data between two computers located 400 miles apart. The network, known as the Arpanet after it was commissioned by the US Department of Defense's Advanced Research Projects Agency, was tested by Charley Kline at UCLA and Bill Duvall at Stanford Research Centre.

Kline attempted to log on to a Scientific Data Systems computer at Stanford, sending the message 'LOGIN' to Duvall one letter at a time. Duvall reported that both the 'L' and 'O' had successfully arrived on the screen of the Stanford computer, but the system crashed before it could receive anything else. Thus, the first word spoken by the internet: 'LO'.

Email in the modern sense was created in 1971. Arpanet contractor Ray Tomlinson picked the '@' symbol from a keyboard to separate the user's name from the computer it was being sent to, and created the email address. The first email was sent from Cambridge, Massachusetts by Tomlinson in the same year. A test message to himself, he sent it from one computer to another sitting right beside it.

It took seven years for email to evolve into spam. The earliest case documented was a message from Guy Thuerk advertising the availability of Digital Equipment Corporation Computers, sent to 393 recipients on Arpanet in 1978.

The first internet worm was launched 10 years later in 1988 by Robert Tappan Morris, a student at Cornell University. According to its creator, the virus, named the Morris Worm, was not intended to cause damage, but to gauge the size of the internet. A detail of the code, possibly erroneous, led to computers becoming infected multiple times, slowing them down to the point of uselessness.

A reported 6,000 major Unix machines were infected by the Morris worm, with the US General Accountability Office putting the cost of the damage between $10m (£6m) and $100m.

In 1989, Tim Berners-Lee and others at Cern proposed a new protocol based on a hypertext system of embedding links into text. The system became publically accessible as the World Wide Web in 1991. In 1990, Berners-Lee also created the world's first web server, known as Cern httpd, which ran on NeXTSTEP, and in 1991 the first website was put online: info.cern.ch.

Phil Male, operations director at Cable and Wireless Worldwide, was involved in the early work on the UK's first academic Internet Protocol networks. In the late 1980s he set up a media business that used internet technologies to distribute data, before moving on to work at Demon Internet, the UK's first commercial internet service provider.

Looking back over the development of the internet, Phil said in a statement that the progress has been exceptional. "This is such a huge change in a short space of time; the magnitude of the adoption rate in terms of culture and technology is phenomenal and to have lived through that and been instrumental in its implementation is just fantastic.”

As of 30 June, 2009, 1.67 billion people had access to the internet, according to the Internet World Stats website; around 25 percent of the world's population.