Elementis shareholder Gatemore calls for strategic review

In its second public letter to Elementis, Gatemore also said the company should consider a potential disposal of the talc business. All these measures, it said, are "essential" to improving performance and unlocking shareholder value.

"The time is now for the board to take immediate and decisive actions to address these governance concerns and realign the company’s strategy with the interests of its shareholders. We have engaged with many of the largest active shareholders of Elementis and believe there is unity on all these issues," it said.

"We strongly urge you and the board to take prompt and decisive action. Failing this, we may be compelled to unite the shareholders and pursue the replacement of the chairman through an Extraordinary General Meeting to drive the necessary change within Elementis."

Gatemore holds around 4.5 million shares in Elementis.

Russ Mould, investment director at AJ Bell, said: "Activist investors often like to negotiate behind closed doors. Private conversations can give the impression they are being helpful and respectful. It’s only when the target refuses to engage or bats them away that activist investors resort to going public with their criticisms and demands.

"That seems to be the case with Gatemore Capital which has published its second public letter spelling out what it wants chemicals group Elementis to do.

"Its latest letter contains the threat that Gatemore might call for an emergency shareholder meeting to oust Elementis’ chairman. Despite the muted market reaction to the letter, it appears that Gatemore’s patience is running out and it is going to turn increasingly hostile to enact change."

At 1405 BST, the shares were down 0.3% at 148.20p.