The NPL network, or NPL Data Communications Network, was a local area computer network operated by the National Physical Laboratory (NPL) in London that pioneered the concept of packet switching.
Based on designs conceived by Donald Davies in 1965, development work began in 1966. Construction began in 1968 and elements of the first version of the network, the Mark I, became operational in early 1969 then fully operational in January 1970. The Mark II version operated from 1973 until 1986. The NPL network was the first computer network to implement packet switching and the first to use high-speed links. Its original design, along with the innovations implemented in the ARPANET and the CYCLADES network, laid down the technical foundations of the modern Internet.
