[Ace] ran for the first time on 10 May 1950. By modern standards it was sluggish but in its day was the fastest in the world.
And, whilst investigating how it could be used, the team uncovered another problem that looked set to dog greater use of computers - how accurate were they?
"When you put decimal numbers in a computer they have to be converted to binary," said Professor Maurice Cox, who also worked on Ace and its descendants. "The conversion is not exact."
"Errors in the data can build up," said Professor Cox. "Those errors can explode if you have an unstable method of calculation."
Jim Wilkinson took on and defeated that uncertainty. Remembered with affection by everyone that worked with him, his work has been overshadowed by Turing.
"He was brilliant in his own right," said Clive Hall, a former colleague of Mr Wilkinson and who oversees some of the computer archives at NPL. "The problem was that he came to NPL when Alan Turing was there."
By splitting data into packets and threading them on the same line, the carrying capacity of that link could be boosted and the whole network made more powerful.
Roger Scantlebury, who worked with Dr Davies, presented the ideas about "packet switching" to a conference in the US, where they were picked up by the creators of the nascent Arpanet, the fledgling internet.
Does that mean Britain invented the internet?
"Yes and no," said Mr Scantlebury. "Certainly the underlying technology of the internet, which is packet switching, we did invent."
Chalk another couple of milestones up to the Brits.