5: Johnson Matthey
The maker of catalytic converters is branching out.

Johnson Matthey is one of the heroes of high-tech British manufacturing, a quiet success story best known as the largest single producer of automotive catalytic convertors - its emissions clean-up devices are fitted to one in three of the world's cars. But under CEO Robert MacLeod it has also begun to branch out into new areas where its expertise in complex chemistry might also bear fruit - such as batteries and fuel cells for electric vehicles. H1 sales and underlying profits both rose 5%, to £1.68bn and £219.6m respectively, helped by a Brexit boost from the feeble pound.