Shares in Chloride soared by more than a third on the prospect of attracting fresh offers, after the power protection group said it had rejected a £657m approach from Emerson Electric Company, its larger US rival.

The UK company, the world’s fourth-largest uninterrupted power supply specialist, said on Monday the 255p a share cash approach from Emerson, the world number one, “materially” undervalued the company and its prospects.