The screw system for adjusting the spanner's grip was invented by Edwin Beard Budding. Like his other invention, the world's first lawnmower, it was made at Phoenix Ironworks, Thrupp.
Before Budding's invention, spanners had to be adjusted with wedges. His spanners made it much easier to hold non-standard hand-forged bolts. Adjustable wrenches using Budding's principle are used all over the world to this day.