NPL network

The National Physical Laboratory Network (NPL Network or NPL Data Communications Network) was a computer network operated by a team from the National Physical Laboratory in England. Following a pilot experiment during 1967, elements of the first version of the network, Mark I, became operational during 1969 then fully operational in 1970, and the Mark II version operated from 1973 until 1986. The NPL network, followed by ARPANET in the United States, were the first two computer networks that implemented packet switching, and were interconnected in the early 1970s.