Updated 23-XII-2013

Ponders End

Ponders End is a factory with a particularly important history due to its long-standing monopoly over the British lamp industry, and because of its association with the invention of many other important electrical devices, such as the first thermionic valve. Its original owners, Ediswan Electric, held the immensely valuable combined patents of both Swan and Edison and the company ruthlessly excercised its power to shut down infringers at every opportunity. It did not adjust well to the competitive industry that sprang up following the expiry of its patents, and the incandescent lamp operations lost considerable market share. Following a series of takeovers lampmaking ceased in the 1950s, with the rest of the site continuing until its ultimate closure in 1969.

Rear View of Ediswan Ponders End Works. Main Entrance from Duck Lees Lane at Upper Left.

Address Duck Lees Lane, Ponders End, Middlesex, United Kingdom
Location Original Factory 51.6461°N,-0.0302°E, New Factory 51.6468°N, -0.0284°E
Opened 1886
Closed Lampmaking ended 1966-67, followed by the rest of the site in 1969
Products Incandescent carbon filament, tungsten filament, projectors, miniature, telephone indicator, automotive, special lamps, Point-o-lite tungsten arc, thermionic valves, cathode ray tubes, small domestic appliances.

Early History
Within five years of the foundation of Swan's electric light company and its swift amalgamation with Edison's British operations to form Ediswan, the company was transformed into one of the most powerful manufacturers in the world. Production was being scaled up with increasing frequency thanks to the combination of three unique pillars of power : the superiority of its lamps in both performance and cost, the strength of its brand name which associated it with the two principal inventors of the incandescent lamp, and the fact that it held the immensely valuable patents of both Swan and Edison, and rather than licensing use of these to its competitors, the company chose to close them down and take over the production volume itself. Perhaps the only other lighting company in the world which enjoyed such colossal commercial power was General Electric of USA, which found itself enjoying similar benefits to Ediswan on the other side of the Atlantic.

By 1886 the company's previous factory at Benwell had reached the limits that could be provided both by that building, as well as the availability of skilled workers that could be drawn from the small town. In March of that year new premises at Ponders End in East Middlesex were identified, in an old Jute mill on Duck Lees Lane. The weaving of Jute was going out of fashion with the local workforce, and the death of that industry provided a conveniently sized industrial site for the rapidly growing Ediswan operations as well as being within ready reach of an almost unlimited pool of human labour, which could be drawn via the railway lines from nearby London. By the end of May 1886 the relocation of machinery, lamp stocks and a substantial portion of the skilled Benwell workforce had been completed.

In the early days Ponders End was a site of monumental scientific significance. Not only because of its pioneering position in the development and manufacture of the incandescent lamp, but also due to the numerous spinoff products that quickly emerged. Countless names of scientific significance spent their formative years at Ponders End - for instance Sir William Thompson (later Lord Kelvin), Sir William Crookes, Sir George Stokes, Sir James Dewar, Dr. Ambrose Fleming, Sir Frederick Abel, Dr. John Hopkinson, and of course Sir Joseph Swan himself. Perhaps even more important for the modern world than Ediswan's invention of the incandescent lamp was the development of the very first electronic valves, which took place under the direction of Dr. Fleming at Ponders End. Valves led on to the development of Cathode Ray Tubes and the already vast manufacturing complex grew further to accommodate these product lines, as well as a whole host of other small domestic electrical appliances.

The End of the Monopoly
Once it had been confirmed in the courts that the incandescent lamp patents of the Edison-Swan company were valid, it perhaps seemed like an obvious commercial strategy to go after all of the other lampmakers in Britain, putting them out of business one at a time and bringing their volume into the Ediswan works to grow its own manufacturing and achieve better economies of scale. In hindsight the directors' greed for growth at the expense of others was probably one of the most short-sighted strategies, for it was this which ultimately led to their own company's eventual demise.

In the monopolistic market, the need for continual research and development to take lamp performance further, and develop new manufacturing techniques to increase quality and reduce cost, was at once gone. Research and Development in lamps and lamp manufacture is a costly business, and no doubt some levels of management must have questioned its need when there was no longer any competition. True enough, looking at just the British lighting market alone this perhaps made sense, but the overseas competitors of course did not stand still.

On the other side of the Atlantic, General Electric of USA adopted an entirely different strategy. It licensed the use of its lamp patents to the smaller competitors and provided incentives for standardisation, to manufacture all lamps according to the same design as GE's own products. This often necessitated the purchase of lamp components from GE's own component factories, earning them a healthy revenue stream on top of the patent royalty that was due on every finished lamp. To main some element of control, GE imposed strict quotas on the quantity of lamps that could be produced by each of the licensees. Similarly in the European countries where the patent situation was much less powerful, with patents even being non-existent in certain lands, the incandescent lamp market was fiercely competitive and intense research was progressing on new and better lamp designs.

Consequently when the Edison and Swan patents expired in 1894, the market in Britain was ripe for the foundation of several dozen new lamp manufacturers, many of which were based on superior new developments or foreign technologies which Ediswan had neglected to follow. No doubt the power of its uniquely strong brand name helped delay its inevitable decline, but within a relatively short period Ediswan had been decimated to a faint shadow of its former glory. The works at Ponders End was increasingly being turned over to the manufacture of other electrical products in which the company did enjoy a stronger and more competitive position.

Philips and the New Lamp Works
The original lampmaking operations were established in the oldest and original part of the former Jute Mill, just to the right after passing through the main entrance gates. It was a building divided into many smaller individual rooms and these were naturally used to house the various lampmaking departments such as filament making, flaring, stem making, mounting, sealing, exhausting, capping, testing and packing. A great deal of manual labour was employed in the transportation of sub-assemblies from one department to another, and this represented a signicant amount of the cost involved in lampmaking. By the mid 1910s developments in lampmaking machinery enabled the various production steps to be brought together onto a single production line, consisting of individual machines to perform each of the former steps and with each machine being synchronised to those alongside it, such that lamps could be made in a continuous line of flow. The transporation of materials from one machine to the next was at first performed with human operatives who no longer had to walk long distances but simply move objects by hand from one stage to the next, however mechanical transfer mechanisms were soon devised to link one machine to the next. The time taken to make a complete lamp, which may have been many days previously, was by 1920 reduced to about twelve minutes spent on a single automatic line.

The new methods of automatic production called for the abolishment of the old departmental system, and the creation of large open areas without hindrance of dividing walls, to house the straight-line production groups. The old building could not provide such space. Moreover during the period of technical stagnation in the monopoly years, Ediswan had not kept up pace with its competitors in the all-important area of machine development, and was not in state to build the required automatic lampmaking equipment on its own. Meanwhile Anton Philips of the Dutch electrical giant was desperate to expand his manufacturing empire to England, and in 1919 he approached the ailing Ediswan with a solution. In exchange for 10% of the share capital in Ediswan he would provide the company with state-of-the-art automatic lampmaking machinery built by Philips of Eindhoven, to allow it to become cost-competitive once again and increase its chances of survival.

Plans were made for a separate new lampworks to provide the large open spaces needed for the Philips machinery, and by the end of 1920 this had been constructed at the far north-western edge of the site and entered service. The installation, operation, management and quality all however fell below Philips' expectations. Friction between the companies was exacerbated when Ediswan fell into arrears in paying for the new equipment - but still paid out a dividend to its shareholders. Anton Philips had to initiate legal procedings to recover the debt, and this soured the relation to the extent that no further co-operation was forseable between Philips and Ediswan. Photographs below show the new building during its construction, and after being filled with the modern automatic Philips lines.

Operation under BTH, AEI, and Siemens-Edison-Swan
Competition in lamp manufacture continued to stiffen in the years after WW1, both from other British manufacturers as well as from the often cheaper European and Japanese producers. Ediswan had still not made up for the stagnation during its monopoly years, and its market share continued to shrink with frightening pace.

In 1926 GE's president Gerard Swope, who was in favour of an amalgamation of the entire British electrical industry to create a single giant force of similar structure to GE in America, recognised the failure of Ediswan and provided the cash to his British subsidiary, the British Thomson-Houston company, to purchase Ediswan outright and combine it with BTH's own lampmaking operations. BTH also took over the 10% shareholding of Philips and Ediswan became a wholly-owned subsidiary of BTH, and hence a part of the GE family. This at once gave the Ediswan works the same access to GE's American technology in lamps and machinery that had allowed BTH to emerge as such a strong competitor, and guaranteed the future of the site for many more years to come.

Ediswan was never fully merged with the BTH lamp manufacturing and sales operations, and continued to operate as a separate entity alongside BTH-Mazda. It is doubtful that the customers would have recognised any change of ownership, for there was no mention of the new parent in the company's literature or on the lamps themselves. At the end of 1928 BTH itself was merged with another electrical giant, Metropolitan Vickers, who had its own lampmaking operation under its Cosmos Lamps subsidiary. Once again it was decided not to merge the BTH and MV lamp businesses, and instead, GE formed in January 1929 a new holding company, Associated Electrical Industries, AEI, which was to oversee the separate entities of BTH, Metrovick and Ediswan along with several other wholly owned non-lighting businesses.

Ponders End grew considerably in lamps under AEI ownership. The strength of the Ediswan brand combined once again with its possibility to offer modern, high performing lamps made to competive prices put it into a particularly favourable position. Those types which could not be made cost-effectively with the relatively expensive London workforce were in 1956 shifted to a new BTH factory at Buckie in the North of Scotland, where labour was considerably cheaper and substantial grants were available from the local government to provide new jobs in Scotland. Telephone indicators were the first lamps to be moved up to Buckie, followed by other specials such as tubular and pygmy, the original carbon and squirrel-cage tungsten types and small projection lamps.

In the same year Ediswan was amalgamated with Siemens Brothers, which had been taken over by AEI in 1954 and had a factory on Strand Road, Preston. The manufacture of some types was exchanged between Preston and Ponders End to streamline the production of each site. The new company was called Siemens Edison Swan, and lamps made after 1956 were very briefly branded with the Sieswan name. Two years later Ponders End grew again, when BTH decided to end lampmaking at its original Rugby works so as to allow that site to concentrate instead on heavy electrical engineering. Rugby's GLS lamps were shifted to a new AEI factory at Trent Vale, while Discharge, Fluorescent and Automotive were relocated to Leicester, and the remaining incandescent types were moved down to Ponders End.

As the later 1950s progressed, AEI itself began to fall into financial difficulties. Primarily this was due to the lack of integration of its heavy electrical businesses, BTH and Metropolitan-Vickers, who fought each other bitterly to win orders. It was not uncommon for one subsidiary to undercut the other's offer, often repeatedly, until there was practically no margin at all left for the company that ultimately won the business. This made the market equally unbearable for the other major players in the heavy electrical business, GEC and English Electric. The entire British heavy electrical industry was failing and from both industry as well as government, there was talk of a full merger of BTH, MV, GEC and EE. Perhaps in preparation for a possible amalgamation of the heavy electrical businesses, AEI Lamp & Lighting Co. was established as a separate entity from the parent AEI Group in 1956, taking control of BTH-Mazda, MV-Cosmos and Siemens-Edison-Swan. The group headquarters was established at Leicester factory. The coming years indeed saw a change in ownership, and during 1958-59, an 11% stake in AEI Lamp & Lighting was sold jointly to its key competitors : 5.5% to each of Thorn Electrical Industries and Osram-GEC. Later in 1959 AEI became a trading company, its name appearing for the first time when it replaced all of the former subsidiary brand names. From this point onwards, the original Ediswan brand was dead, along with Siemens, BTH, Metrovick and Cosmos. All lamps of the group were thereafter sold under the AEI-Mazda brand.

Transition to Thorn
In 1959 AEI merged its small domestic appliance business "Hotpoint" with Thorn, which included part of the production at Ponders End. Two years later in 1961 AEI's Valve and Cathode Ray Tube division, much of which was based at Ponders End, was also amalgamated with Thorn Electrical Industries, this time with Thorn taking 51% of the shareholding. The ownership of the Ponders End site was thus split for the first time, with Thorn taking control of some departments and the balance remaining with AEI. As AEI's financial situation continued to plummet from bad to worse, Thorn also had his eye on the entire group's lampmaking operations, for which he made a historic bid in December 1964, taking at once a 65% stake in AEI Lamp & Lighting Company, including of course the final part of Ponders End, the Lamp Works. A new holding company, British Lighting Industries was formed under Thorn, to fully integrate each of the different lampmaking companies that had fallen under its control in recent years.

Thanks to Thorn's close technical alliance with Sylvania of America, one of the most skilled companies in the world in the development of high speed and high efficiency lampmaking machinery, Thorn's own lamp factories were considerably more valuable than anything contained at Ponders End. The lampmaking division was closed in 1966-67 and the volume absorbed by Thorn's factories. Shortly afterwards the Valve and CRT division met a similar fate, shifting into Thorn's Mullard tube works at Brimsdown. By 1969 all production had ceased at Ponders End, and the site was demolished in 1970.

Ponders End Developments
Aside from the aforementioned development of the Thermionic Valve, there were also some notable firsts in lamps that were developed at Ponders End. One of these was the "Fullolite" lamp, introduced in 1921, which was the first lamp mass produced in Britain with highly diffuse opal glass. It is suspected that the technology to make this lamp may have been acquired following the 1920 agreement with Philips, which itself became a pioneer in the cost-effective manufacture of opal lamps by flashing a thin coating of white opal glass onto an ordinary clear glass bulb, a process which was considerably cheaper than blowing bulbs from solid opal glass.

Thanks also to the association with BTH, in 1927 Ponders End became one of the first factories to produce lamps in internally acid-etched pearl glass bulbs.

Ediswan did not exploit the electric discharge lamp to the same extent as its competitors, but was responsible for the development of the most peculiar, and rather successful Point-o'-Lite lamp.

View from Factory Gates, 1903 Flood New Lamp Works, 1920 New Lamp Works, 1920 Aerial View, 1921
Aerial View, 1921 Aerial View, 1921 Aerial View, 1921 Aerial View, 1921
Carbon Lamp Sealing c.1910 (Ref.6) GLS Department c.1945 (Ref.1) Lead Wire Welding c.1945 (Ref.1)

Examples of Ponders End Lamps

Carbon Filament
Azure Carbon Lamp Opal Carbon Lamp Iced Glass Carbon Lamp Thermalite Carbon Heat

Gas Discharge
Pointolite Tungsten Arc Neon Indicator Neon Pygmy

1 The Pageant of the Lamp, Published by the Edison-Swan Electric Company Ltd., approx. 1948.
2 The Monopolies and Restrictive Pratices Commission, Report on the Supply of Electric Lamps, 1951.
3 The Monopolies and Restrictive Pratices Commission, Report on the Supply of Electric Lamps, 1968.
4 Anatomy of a Merger : A History of GEC, AEI and English Electric, R.Jones & O.Marriott, Pan Books Ltd, 1970.
5 Death of a Lightbulb, J. Otten, Blue Ocean Publishing 2012.
6 The Electric Lamp Industry, G.A. Percival, Sir Isaac Pitman & Sons, 1920, p.64.
7 Britain from Above, Aerial Views