Could the FV4005 have changed history? With its massive 183mm cannon, this British tank had the potential to destroy Soviet ...

The completed vehicle was running by the end of 1915 but by then a new design was under construction and this would become the prototype for all British heavy tanks in the First World War.

This week the Telegraph is running a series of exclusive essays by expert commentators looking into Britain’s “hollow” armed forces.

Russia’s astronomical losses in the conflict so far have wiped out its most skilled units, forcing it to rely on mass conscription for further advances.

The completed vehicle was running by the end of 1915 but by then a new design was under construction and this would become the prototype for all British heavy tanks in the First World War.