No 3: Spirax-Sarco Engineering
The steam specialist's share price has risen 150-fold since the turn of the millennium.

A sparkling third for Cheltenham-based steam specialist Spirax-Sarco Engineering, making it to the podium in only its second-ever top 12 appearance. Its systems are used in everything from brewing and food production to pharmaceuticals, precious metal processing and oil refineries. Thanks to a string of savvy acquisitions under boss Nicholas Anderson and a disciplined performance in emerging markets, its share price has risen 150-fold since the start of the century. In May, it acquired US thermal technology business Chromalox for £319m.
Image credit: Spirax-Sarco Engineering