Ferranti digitising table and computer. This is one of the first units that are different to the later models with an all-in-one unit but this had a separate freestanding computer and tape drive. These would have cost about £8000 at the time, which could have got you a Rolls Royce Silver Shadow.
This had a dial to set the rate of stream digitising, it was set to 6 points a second but this approach made it impossible to get an accurate result. Colonel Gardner Hill created a mathematical spline for generating curves, which had a much smoother result.
This actual digitiser, no 1, is now at the Science Museum after kindly being donated by OS, as it is a key part of the digital transformation that OS went through in the post-war years.