Breton-Pretot machine

Breton-Prétot machine
The Breton-Prétot machine, in July 1915. The top picture shows the vertically stacked cannon; below it the original tractor version
Type	Armoured wire cutter
Place of origin	France
Service history
In service	1915 (experimental)
Specifications
Weight	4 tonnes (+1 tonne for armour)
Crew	3
Engine	gasoline internal combustion engine

The Breton-Prétot machine was an experimental wire-cutting device developed in France from November 1914. It was developed by Mr. Prétot, engineer, and Jules-Louis Breton, member of the French National Assembly.

The immobility of the trench warfare characterizing the First World War led to a need for a powerfully armed military engine that would be at the same time protected from enemy fire and could move on the extremely irregular terrain of battlefields. Barbed wire especially posed a considerable threat as it was cheap and easy to install, extremely effective at slowing or stopping an offensive by troops against protected fire, and very difficult to eliminate, even with artillery. Special machines were considered to attempt to eliminate this problem: armoured, armed vehicles, with a capacity to flatten or otherwise eliminate barbed-wire lines.

The Breton-Prétot machine was a saw designed to cut the barbed wire protecting enemy trenches of World War I. The first version consisted of a small circular saw, driven by a six hp engine, attached to a long lever that was placed on a small cart with four wheels, that had to be pushed towards its objective. Breton proposed the machine to the French government in November 1914 and a prototype was tried in January 1915, when it was shown that the system in this form had little practicality. The use of caterpillar tracks was discussed that same month, but since none was available at that time, the system was then mounted at Liancourt on the back of a Bajac tractor in an attempt to obtain all-terrain mobility, towards the end of February 1915. The small circular saw was replaced by a large vertical saw with thirteen teeth, but a larger horizontal circular saw was added, just above ground level to cut the barbed-wire poles. In July the system was again changed, the horizontal saw being left out and large deflection shields being placed to protect the wheels. Eight small bronze cannon were used as simulation weights.

After satisfactory tests on 22 July 1915, at Maison-Lafitte, the War Minister, Alexandre Millerand, ordered ten armoured and armed wire-cutters to be manufactured on 7 August.