[This post is a lightly edited version of the last chapter of my book; it assumes a bit of knowledge about the history of Manchester computing that appears earlier in the book or can easily be found on eg Wikipedia. Williams is Frederick Calland Williams, who was recruited to Manchester by Patrick Blackett and Max Newman but rapidly made Newman’s Computer Laboratory his own; Kilburn is Tom Kilburn, William’s junior and then successor. ]

The men of experiment are like the ant, they only collect and use; the reasoners resemble spiders, who make cobwebs out of their own substance. But the bee takes a middle course: it gathers its material from the flowers of the garden and of the field, but transforms and digests it by a power of its own. Francis Bacon, around 1620.

There are today two separate blue plaques on the same building complex off the Oxford Road, but you can’t seem them both at the same time. There is one facing north shared by Williams and Kilburn, and after you take an inconvenient diversion around the Manchester Museum, there is one facing south for Turing, in a physical representation of a difference in viewpoint that has rumbled on ever since the events of 1948. Neither plaque says anything untrue but then again neither plaque mentions the other. They represent a history that portrays Kilburn and Williams as one type of thinker and Turing as another. In this history Kilburn and Williams are labelled as doers, as what Francis Bacon would call ants, while Turing is a reasoning spider. But both plaques decorate Manchester, the city of the bee, whose rightful reputation as a birthplace of the computer depends inextricably on all of three of those named, and on everyone going beyond stereotypes. One of the many profound consequences was that it was the child of two Manchester spiders — Tim Berners-Lee, whose parents Mary Lee and Conway had met as programmers at Ferranti — who should create the world-wide web.

For most of the twentieth century, the history of Manchester computing simply started in 1948. This said that Williams and Kilburn had been interested in the engineering challenge of making, rather than programming, a computer and that, it went, is what they succeeded in doing: ‘Freddie Williams was not, I think, interested in the computer as a computer. What we were interested in doing was creating the computer for other people to use’. In this account Newman’s computing project had been an unsuccessful rival to Williams’, an account helped by Newman’s own lack of credit-seeking behaviour. When a historical Turing re-emerged after 1983, it was as a National Treasure residing at Manchester at the time but with no relation to the machine, except through using it for his impenetrable biological mathematics. In 1998 the Department of Computer Science held a 50th anniversary celebration to mark the first running of the Baby: Turing, it’s said, was not mentioned on the day, and in 2006 one leading local computer scientist said ‘Colossus was not a machine in the direct line leading to the modern computer’. This engineer’s history can’t be said to be wrong, but it is partial.

It wasn’t until the twenty-first century that the pre-Mark I history of the Manchester computers was quarried by revisionists aiming to re-establish the role of the mathematicians. They pointed out that, even years after the event, Williams had always been generous in acknowledging the mathematicians’ influence and had no difficulty recalling that Tom Kilburn and I knew nothing about computers…Professor Newman and Mr AM Turing knew a lot about computers. They took us by the hand and explained how numbers could live in houses with addresses. In 1948, it was as electronic engineers, not as computer architects, that Williams and Kilburn led the world. Kilburn, by contrast, was much more grudging: ‘Between 1945 and 1947 somehow or other I knew what a digital computer was…where I got that knowledge from I’ve no idea’. In fact he had got it from attending a series of lectures: the lectures given by Turing. It’s unlikely that Kilburn in these later comments was deliberately obscuring credit due to Turing, and more plausible that he just didn’t remember owing anything to the mathematicians. As a young PhD student Kilburn was not interested in the past, and quite insulated from the administrative background. There is no patent on an idea, or on a funding decision, and rightly it was Kilburn listed as inventor on the computer memory patents, not Turing or Newman or Blackett.

The final glimpse we have of Kilburn and Turing working together is over a long summer night in June 1950. After the somewhat fake demonstration for the BBC of doing Mersenne mathematics on the Manchester Mark I there had been a year of work by Turing on an actual research problem. Turing had developed code to explore a pure mathematical axiom known as the Riemann Hypothesis, and that, together with some work on an optical problem, may have been all that the machine did for a year. Finally, in June 1950, the Riemann code ran successfully, all night: ‘The calculations had been planned some time in advance but had in fact to be carried out in great haste. If it had not been for the fact that the computer remained in serviceable condition for an unusually long period from 3 p.m. one afternoon to 8 a.m. the following morning it is probable that the calculations would never have been done at all’.

An engineer had to be on standby whenever the machine ran and it was Kilburn who stayed overnight with Turing and ensured the unusually long up-time. This was the first application of the Manchester computer to generate a mathematical paper, but it was also the time at which Kilburn began to realise that the aims of the Manchester logicians and (perhaps unknown to him) cryptographers were very different to those of the applied mathematicians using computing resource elsewhere in the world. Henceforth, he said, he would address the latter, and in doing this he chose a group of consumers with practical, well-funded, and plausible needs who would in fact drive the economic development of the computer for decades. It meant that Manchester computers would be used to do the large repetitive calculations needed by the atom bomb projects. This was the opposite use to the automated reasoning that Newman and Blackett had intended. Newman seems to have accepted this, though it took Manchester off a path pointing to intelligent machines. Blackett, on the other hand, was unhappy, perhaps because of his opposition to atomic weapons themselves. But Blackett no longer had any leverage over the project.

Though Kilburn and Turing worked together in the early days, they never collaborated in any intellectually meaningful way. Had they done so, the potential for an early breakthrough in artificial intelligence would have been enormous. They were two people of creativity and achievement, with much knowledge and background in common, and with different and complementary skills in a field ripe for innovation. But something about those differences kept them apart. They were both productive bees, but one looked like an ant and one a spider. This is a story where it is very tempting to align two men on opposite sides of an apparently intuitive divide. Asked to assign one member of each pair from: North/South, Manchester/Cambridge, grammar school/public school, engineer/mathematician, applied/pure, doer/thinker, hardware/software, trade/gentry, earned/entitled, patent holder/private thinker, the labels that apply to Kilburn/Turing might seem at first obvious and factual. Binary reductions are as addictive as they are misleading, so that adding into the list masculine/effeminate, straight/gay, legal/illegal might give hardly more pause for thought. It is only a short step after that to a conclusion that manly Manchester’s judgement of Turing as an effeminate Cambridge criminal led to ostracism and Turing’s depression and suicide. But it is a circumstantial step without direct evidence.

There is clear evidence that there was coldness. Perhaps it was the engineers that felt looked down on: some of the mathematicians considered Williams and Kilburn as not ‘ideas men’. Williams later gave a lecture, Engineering Must Not Degenerate Into Mathematics, which under cover of a successfully jocular tone revealed a distinct bitterness about the class distinctions in the ‘traditional aristocratic attitude: to be really tops two things are required: (a) one must be supremely good at something. (b) The something at which one is supremely good must be absolutely useless’.

It was more than class, though. Kilburn and Turing are recorded by multiple sources as not getting on, and Geoff Tootill, in long hindsight, speculated that this was because Kilburn knew of Turing’s sexuality. But after this the binaries start to fray. Tootill also thought there may have been disapproval of Turing’s general untidiness and tendency for his underpants to show above his trousers, and another programmer thought Kilburn in general liberal and broadminded. The dichotomies don’t always survive inspection: Kilburn had had a Cambridge mathematics education too, and Turing also came to Manchester through choice and with hands-on electronic expertise. And though to begin with Turing was paid more than Kilburn, by 1954 Kilburn’s career prospects and consulting fees were rapidly improving. There may have been a ‘jagged rift’ between the engineers and the mathematicians, but it was perhaps more a silence of incomprehension than anything more destructive. One heir on the programming side wrote: ‘Turing, Kilburn, and Williams, were all three quite different people…stars of the scientific establishment to my mind…good, kind people’.

Whatever the reasons, Manchester’s Electrical Engineering department, and the Computer Science department that succeeded it on the Oxford Road, became a place where people made computers more than one where they used them. The place of the Manchester Mark I in the history of computer development is secured far more by its hardware than by its software. The histories of the '50s and '60s are histories of ground-breaking machines more than of programs. In hindsight, that may have been a poor long-term bet. For a few decades Moston and then Gorton were the sites of factories that made mainframe computers; meetings of the Lit & Phil can still attract the men and women who made them. But the engineers who can say they have built computers in Manchester are all now retired. Although the Ferranti Mark I had the largest share of the new market, British hardware rapidly started to lose out to American machines on reliability and cost. Within a few years of the delivery of the Ferranti Mark I to AWRE, the British atom bomb designers were demanding an IBM replacement, not a British one, and certainly not Kilburn’s Atlas. Large, centralised computing facilities based around IBM hardware did evolve locally, and Shell, Barclays and the TSB all set up large new centres in Wythenshawe. Today computing power has become a commodity, provided by huge server farms who choose not to advertise their physical location, and if Manchester is still a significant provider of information processing capacity to the UK we have no accurate way of knowing: in any case the industrial estates of Manchester no longer make computers, or even disk drives.

But Manchester is still visibly home to a thriving, if small, software industry, though the Kilburn building still, to the surprise of some newcomers, makes little of the connection between the Computer Science Department and Turing as local hero and founder of Computer Science. The red brick building, glazed with narrow slits in a 1970s version of housing for machine acolytes, sits across a bare plaza from a more transparent glass and steel Mathematics building which is named after Alan Turing. When the mathematicians planning that twenty-first century development had warily enquired if Computer Science had any major developments they wanted to name after Turing, the mathematicians were emphatically told that if Turing had lived longer he would have set back computer science by decades and that the mathematicians were welcome to him. And so they are.

(Notes and references can be found in the book or on request).