Invensys, the engineering technology group, saw its shares slide nearly 18 per cent on Thursday as an improvement in turnover, profits and order book levels failed to quell fears of the impact of weakening demand from manufacturing clients.

Ulf Henricksson, chief executive, said demand continued to be strong in its railway controls and industrial automation divisions, which provide software and production systems to the oil and gas, petrochemical, refining and power sectors.