Mother / Big Willie / HMLS Centipede

British prototype tank Mother in 1916. The image depicts the prototype, not a production Mark I.British Government photographer / Wikimedia Commons / Crown copyright expired.Image source

The prototype behind the Mark I

Mother was the British rhomboid prototype that connected the early Lincoln experiments with the production Mark I. The names Big Willie and HMLS Centipede also occur in the available evidence. The names are aliases of the same prototype rather than separate vehicles. Sources

The distinction from Little Willie is physical and technical. Mother used a different hull and track geometry to meet obstacle-crossing requirements that the earlier arrangement had not satisfied. Its tracks rose around the body, and its armament arrangement used side sponsons rather than a central turret. Sources

Mother also differ from the Mark I tanks that subsequently entered combat. The production family demonstrated the consequences of the prototype program, but its battle photographs, standard crew, ammunition allowances, and operational modifications cannot automatically be attributed to the experimental vehicle. Sources

Construction and the 1916 demonstrations

Accounts place Mother’s construction in late 1915 and records its first movement under power at Lincoln on 13 January 1916. Its development drew on the work associated with Tritton and Wilson, but the rhomboid layout was a change in the way the vehicle approached the ground, not merely the earlier hull with a new name. Sources

The trial sequence then moved to Hatfield. The chronology records rail movement on 28 January, preliminary trials on 29 January, the major official demonstration on 2 February, and a royal demonstration on 8 February. These are distinct events; a photograph labeled broadly ‘1916 trials’ cannot be assigned to one of them without supporting evidence. Sources

The demonstrations helped lead to orders for the production Mark I. Accounts describe an initial order of 150, divided between Male and Female armament forms. That production result belongs to the successor’s history and does not turn Mother into a family of 150 prototypes. The experiment and the subsequent manufacturing decision are connected but separately counted. Sources

Rhomboid layout and prototype specifications

The raised track runs and extended overall shape were intended to help the vehicle approach and span obstacles. Side sponsons carried the weapons, while the rear steering wheels formed part of the trial configuration. The arrangement gave Mother a recognizable relationship to the Mark I. The cited accounts do not firmly establish individual features and fittings. Sources

The references identify a Hatfield program as the basis for a weight of 28 tons 8 hundredweight and an overall length of 31 feet 3 inches including the tail. A tail-inclusive length is not a hull-only length. Sources

Several other figures in the reference material are drawn from the Mark I or used by analogy with it. The commonly quoted Mark I armor, crew, speed, and ammunition values does not establish unqualified Mother specifications. Sources

The safest technical presentation distinguishes a documented prototype measurement from a plausible family resemblance. Where the prototype’s exact crew, armor material, gun fit, or transmission condition has not been established,. Sources

After the trials

Accounts describe the removal of weapons after demonstration work and later use in development and training contexts. It also records a subsequent Daimler petrol-electric experiment associated with the prototype. Sources

Mother did not acquire a combat career simply because the Mark I did. They are not evidence that Mother served in those engagements. Sources

The available evidence similarly distinguishes the prototype from the later British Marks and from supply or wireless conversions. Sources

Disappearance and the limits of the evidence

The prototype’s eventual fate remains unresolved in the cited sources. Accounts differ between scrapping and burial. Sources

The account discusses a 2025 search initiative and a rediscovered letter relevant to the burial account. That is evidence of an investigation and its documentary basis, not a report that Mother has been recovered. Sources

This uncertainty is part of the historical account rather than a defect to conceal. Readers can understand that an important vehicle is missing, why researchers are investigating different explanations, and what type of new evidence would change the conclusion. Neither a reconstructed image nor a photograph of a Mark I can settle the question of the prototype’s physical survival. Sources

A gallery that identifies the actual vehicle

Two of the four photographs embedded in the cited record illustrate Mother itself: a side view of the prototype and a trial view at Hatfield. A larger digital enlargement does not reveal historical detail absent from the underlying photograph. Sources

The other two images show production Mark I tanks identified in the cited sources as C15 and C19. They are useful for the development-to-service connection, but belong in a clearly marked successor context or the future Mark I article. They are not two additional independent views of Mother. Sources

This produces a coherent article about one vehicle rather than an amalgam of the entire early British tank program. Sources

Photographs and image credits

Background reading and references. Each photograph has its own source and credit.

Mother during trials at Hatfield Park in 1916; the exact demonstration date is not established by the year-only date.British Government photographer / Wikimedia Commons / Crown copyright expired.Image source

Sources and further reading

Background reading and references. Each photograph has its own source and credit.

The prototype behind the Mark I

Construction and the 1916 demonstrations

Rhomboid layout and prototype specifications

After the trials

Disappearance and the limits of the evidence

A gallery that identifies the actual vehicle

Photographs and image credits

Sources and further reading

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