The Turing Machine is a theoretical model of how computation takes that inspired the pioneers who created the modern digital computer.

Turing described the machine in the seminal paper, On Computable Numbers in 1936.

In the paper Turing described the hypothetical machine as being able to move backwards or forwards over a strip of infinite tape, which is divided into cells. The machine could read, write or erase symbols inside each cell.

The machine would be controlled by a series of rules that tell it whether to move the tape, how to manipulate a cell's contents and which rule to jump to next.

Photo: Bletchley Park Trust