The first electronic computer to go into general use that did not need to be rewired by hand for every new task – marking the birth of everyday computing – was celebrated with the unveiling of a Blue Plaque at Cambridge University.

The plaque commemorates the development of EDSAC in Cambridge – a landmark event in the history of modern computing – and is the first Cambridge & District Blue Plaque to mark the creation of a machine.

The Electronic Delay Storage Automatic Calculator weighed two tons and took up a whole room at the University’s then-Mathematical Laboratory (now the Department of Computer Science and Technology). When it came into operation, in May 1949, it was the first practical machine of its kind : a general purpose digital electronic ‘stored-program’ computer, which could hold both instructions and data in the same memory.

EDSAC was truly groundbreaking – it enabled researchers to do work that had previously been impossible and in so doing, opened up new fields of science. It contributed to three Nobel Prizes in the 1960s and 1970s (for Chemistry, Physiology or Medicine, and Physics, respectively), and its immediate successor, EDSAC 2, was used by Francis Crick and James Watson as they continued their research into DNA, following their discovery of its structure using crystallographer Rosalind Franklin’s experimental evidence.

Though not the first computer built in the UK (Manchester University’s experimental 'Manchester Baby' preceded it by 11 months), it was the first fully functional computer to be used practically. And as it was thousands of times faster than the mechanical calculators of the period, EDSAC was immediately put to use to help scientists across the University carry out complex calculations. Real-world problems that had previously been impractical to attempt could now be solved.

The Blue Plaque to commemorate EDSAC has been created by Cambridge Past, Present and Future. Their Cambridge & District Blue Plaques mark the people and events that have shaped the city and surrounding villages, making history visible in the streets where it happened.

“I’m absolutely delighted that we are commemorating the EDSAC with a Blue Plaque,” said Professor Alastair Beresford, Head of the Department of Computer Science and Technology at Cambridge. “Both the machine and the science it enabled were truly groundbreaking. The legacy of this work can be seen across the Department today, where our staff and students continue to deliver world-class research, actively collaborate with industry, and launch world-changing companies.”

Mike Hakata, Chief Executive, Cambridge Past, Present and Future, said: “Every day, billions of people benefit from technologies whose origins can be traced to pioneering computing work carried out in Cambridge. The EDSAC represents a turning point in that story, when computing moved from theory into practical reality. Through our Blue Plaques programme, we aim to connect people with the places, people and ideas that have shaped Cambridge and changed the world. We are delighted to recognise this extraordinary achievement and ensure its story remains visible for future generations.”

EDSAC’s creation was led by legendary computer science pioneer Maurice Wilkes. His work on radar technology during the Second World War gave him the idea for how to create EDSAC’s memory. He also benefited from a visit to the USA in 1946 to learn about their world-leading work in computer engineering. The ideas he brought back to Cambridge helped him and his team develop EDSAC and get it into operation in May 1949.

EDSAC could execute approximately 650 instructions per second. While modern computers operate millions of times faster, in the late 1940s and 1950s EDSAC offered a massive improvement on what was possible at the time. The first computer ever built at the University, it is said to have increased productivity 1,500-fold, transforming scientific research.

By the standards of today, it was immensely cumbersome to use: researchers had to translate their instructions into a program punched onto paper tape, which was then fed by hand into the machine. And the queue of programs waiting to be run on the computer was no more sophisticated than a washing line, with a series of hooks and clips to hold the tapes.

Nonetheless, EDSAC was game changing. Ideas about computing that were developed then – such as subroutines – still belong in the basic stock of computing knowledge today. Cambridge computer scientists also contributed to the early development of computer programming languages and operating systems.

EDSAC was the first in a whole line of computers created over the years at Cambridge University. Other notable contributions by the Department include working with Acorn on the BBC microcomputer in the 1980s, which, along with an accompanying BBC programme, encouraged huge growth in computing as a hobby. And in the early 21st Century, staff and alumni helped to establish a charity to produce the Raspberry Pi, the best-selling and most successful UK computer of all time.

Today, Cambridge University’s Department of Computer Science and Technology remains a world leader in its field, conducting pioneering research across many areas of computer science, including computer architecture.

The EDSAC Blue Plaque was unveiled at a special ceremony in the Department of Computer Science and Technology. Later this summer, it will be installed on the David Attenborough Building, a University building in the centre of Cambridge where the machine was originally built.

Words: Stephen Bevan and Rachel Gardner
Image: Cavendish Laboratory and Cambridge Past, Present and Future
Published: 24th June, 2026

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